Introduction to Common Law
The term Common law refers to the legal system that has developed through judicial precedents under English legal tradition. England was ruled by Anglo-Saxon rulers before the Norman conquest. Unwritten local norms that varied by community or tribe regulated the English people. Following the Norman Conquest in 1066, a unitary system under the control of centralized power in the form of a sovereign king started to develop. Henry II was a prominent figure in the institutionalization of common law, establishing a uniform body of law that was "common" to the nation by compiling the best customs or rulings of several courts. Common law is the result of precedent set by a court verdict and regional tribal customs.

Nearly a third of all the people alive today live in regions where the law has been more or less strongly marked by the Common Law.¹ Colonialization allowed the British Empire to establish itself on vast foreign territories after centuries of hard work. From the historical standpoint, there were two categories of British colonies. In the first group, the common law of newcomers was automatically applied in areas where political and legal institutions were still in their early stages, like North America. In the second group, common law was selectively transplanted into countries where political and legal institutions had already grown and colonial power left the existing laws intact, like India.

Coming to the age of 21st century, we can observe how common law is applied in the English legal system, where it is specifically applied in English jurisdiction, the place of its origin, and in the legal systems of the nations where common law was introduced as a result of British colonization. The United States of America, many other Commonwealth, and former Commonwealth countries retain the Common Law System. ² Even though these nations have achieved independence, common law continues to have an influence on their legal systems, including the American legal system.
 
English Legal System
The law that applies in England and Wales through the combination of case law and legislation is known as the English legal system. Common law originally developed in England during the Medieval Period. Though both English law and Common law refer to the same kind of law that originated in the same place, Common law usually describes a legal system based on judicial precedent and case law that originated in England and is currently being used in many other countries, whereas English law is the specific application of common law within the jurisdiction of England. Before the Norman conquest, England had several tribes guided by its local customs. After William the Conqueror conquered England in 1066, the attempts to unify such customs started. Through the efforts of itinerary judges, the common customs and verdicts were compiled to form a common law. The law developed as a result of judicial reasoning and compilation of common customs. The use of precedent doctrine and unwritten laws are two major features of the English legal system.

The nature of English law and the course of its development were fundamentally affected by the fact that very early in its history, a class of jurists who organized  a kind of guild and exercised political influence. Since, the King’s entourage and the royal courts (which gradually emerged from it) were all located in London in the early Middle Ages, they attracted a large number of individuals skilled in law (who were mainly churchmen to begin with but later included laymen as the knowledge of law spread outside the church ³). Customs, precedents, statutes, and juristic writings serve as the sources of the English legal system in today’s time. With an unwritten constitution, the English Law System adheres to parliamentary supremacy, which means Parliament has absolute law-making authority and there is no provision of ultra vires regarding laws created by Parliament.

American Legal System
The American Legal System is an offshoot of common law developed after British colonialism. The English started settlement in North America in the first half of the 17th century. At the beginning of the 18th century, there was an increase in trade between the colonies and abroad, and theocratic rule began to lose its hold, and classes of lawyers gradually arose who were trained in Inns of Courts in London. Law books like Blackstone’s commentaries became widespread. The English subjects carried common law with them when they settled in new lands, not under the control of a civilized nation.⁴

After the Independence of America in 1776, the representatives of independent states came together to draft a fundamental law of the land and agreed that common law should be the law of the states while identifying their unsuitability, which allowed many American courts to modify English common law in many respects. As a result of that, the matters of private law in the United States of America emerged from common law, and the matters of public law were developed on their own. The law of the US traces its origins to England, and therefore it is referred to as ‘Anglo-American Law,’ sharing numerous common characters. Following the Confederation, the United States Constitution was enacted on 4th March,1789 with common law serving as the legal framework that established  principles and precedents. Today the constitution, administrative law, precedents, statutes, and equity serve as the sources of American law. America practices federalism along with a dual-court system, which means there exist federal courts and state courts to hear cases under their own jurisdiction.


Comparison between English legal system and American legal system

Today the legacy of common law has been carried out by England and Wales and by those nations colonized by Britain. Deeply rooted in the foundation of the common law philosophy, English and American law and legal systems share many features.
However, as they have grown more mature, they have obtained staunchly different legal features that work to define their legal system.⁵ The following are the similarities and differences between both systems.

SIMILARITIES

1. Adherence to Common Law: Common law is a collection of legal opinions from judges that explain their decisions in specific cases. The English legal system is based on common law, which combines laws enacted by parliament with case law that applies in England and Wales. Even though American law has created many of its own legal structures and rules, its roots are in the common law that was introduced during British colonization. Common law was applied and modified by American courts in different ways. The common law, in one or another of its usages, has always been among the most popular topics of scholarly research in England and America ⁶. Today, common law has been upheld by both legal systems. Doctrine of Precedent, Adversarial System, Freedom of Contract, and Jury Trial are the features adapted in these legal systems.

2. Use of Jury Trial System: The jury system is a judicial process during a trial of a case in which a group of people known as the jury decide the question of fact in the case. In both the English and American legal systems, the jury system is used during the trial proceeding to decide the factual issues, and the judge decides the legal issue. Usually, both systems utilize a jury consisting of 12 people. The jury members are selected from the community and serve on a temporary basis. Although both systems use the jury in trials, there are few distinctions between the procedures followed as selection process, verdict, and the types of cases that include jury. In the US, jury is used for both civil and criminal cases, whereas in the UK, use of jury in civil cases is an exception.

 
3. Doctrine of Precdent: Common law is developed from judicial precedents and customs. The judges are the molders of the common law, and each holds a broad understanding of the precedents ⁷. The doctrine of precedent in the United States and the United Kingdom is similar in the sense that both legal systems primarily rely on the principle of "stare decisis," which states that courts must follow earlier verdicts in cases that are similar, essentially using past rulings as a guide for future judicial decisions. The verdicts of higher courts are rendered binding on lower courts which helps in the interpretation of statutes and the formation of new rules.

4. Role of Supreme Court: The US and UK Supreme Courts share a number of similarities. Both serve as the highest appellate court in their jurisdiction on crucial matters of domestic law. Both hear only a limited number of cases each year tending to legal questions of great legal importance. And both issue judgments which are binding on inferior courts across their respective jurisdictions. ⁸

5. Position of Statutes: Statute means the law enacted by legislation. Statute serves as an important source of law in both the English and American legal systems. Parliament of the respective systems enacts statutes, and the process is similar. The bill gets presented in the house and is discussed, and once it is passed, it is assented by the head of government, i.e. the monarch in the UK and the president in the USA. Statute helps to fill the gaps where law hasn’t been already developed.

6. Adversarial System: The adversarial system is a method in which each party to the case offers argument and evidence in support of his or her version of events to the court, and the court judges whether the party that initiated proceedings has established their version of events to the relevant standard. The common law system follows an adversarial system in court proceedings. As English law originated through common law, the parties play a significant role in presenting evidences and arguments on their favor whereas judges play the neutral role. While the American adversarial system is rooted in English common law, its development was influenced by differing colonial needs.⁹ In such system the role of judge is passive and the role of the parties is active and this system can be observed in both English and American Law System.

7. Role of Judges: In common law system, judges play an important role in interpreting and applying the law along with development of legal principles through judicial decision. Judges have played the role of jurists in this system. When courts interpret they cause statute to grow or contract. This interpretation becomes parts of the statutes or orders, thus giving them meaning in the spirit and application of the common law. ¹⁰

DIFFERENCES
The following are the differences between both systems:

1. Court Structure: The court structures between these states differ from each other. England and Wales share a unified court system based on common law principle with four tiers of court, i.e. Trial court, High court of justice, Appeal court, and Supreme court.
The cases of first instance goes to Magistrate Court (if criminal) and County Court (if civil). The High Court includes Queen's Bench Division, Chancery Division and Family Division. The second court in the hierarchy is Court of Appeal and finally Supreme Court which is the highest level of court. 
On the other hand, the USA has adopted a dual-court system. The dual court system refers to the co-existence of two separate court systems in the United States: the federal and state court systems. While the federal court system has jurisdiction over cases that involve federal law, the state court system has jurisdiction over 
cases that involve state law.¹¹ However, the appeal to the State Supreme Court can be heard by the Federal Supreme Court if the State Supreme Court has declared any federal law invalid or upheld the validity of state law. While cases are heard by courts under the same structure in English law, the US courts hear cases on the basis of their jurisdiction as per federal and state law.

2. Applicability of Precedent: Both English and American Legal Systems follow the doctrine of precedent, but differences arise in the bindingness and flexibility of the precedent. Precedents are more flexible in the USA, whereas they are more rigid in the UK. In England and Wales, the courts operate a rigid doctrine of precedent, where every court is bound to follow any decision made by a court above it in the hierarchy, and in general, appellate courts (courts that hear appeals) are bound by their own past decisions.¹² On the other hand, in the USA, the verdicts of federal courts are binding to other federal courts, and the verdicts of state courts are binding to courts under its circuits. English courts are more bound by the decisions of earlier cases and adhere more strictly to precedent, whereas US courts are more free to deviate from or overturn past rulings based on the situations.

3. Practice of plea bargaining: Plea bargaining is a process whereby the defendant pleads guilty in exchange for a lighter sentence or an agreement to drop additional charges. In the United States, plea bargaining is very common; in fact, it is used to settle the great majority of criminal cases and recognized as well. When the government has a strong case, the government may offer the defendant a plea deal to avoid trial and perhaps reduce his exposure to a more lengthy sentence. A defendant may only plead guilty if they actually committed the crime and admits to doing so in open court before the judge. When the defendant admits to the crime, they agree they are guilty, and they agree that they may be “sentenced” by the judge presiding over the court—the only person authorized to impose a sentence. ¹³ Plea bargaining is comparatively less recognized under English law. Although it isn't specifically permitted, the prosecution and defense may negotiate possible plea agreements.
 Any agreements reached between the defense and the prosecution cannot bind the judge, who still has complete discretion over the sentencing.

4. Legal Profession: The legal profession under the English system is divided into categories- Barristers and solicitors with respective responsibilities. The barristers represent clients in the courts, whereas the solicitors perform non-legal works or work outside of the court. The qualification to be a legal professional is to either complete law degree or attain GDL if you are a non-law graduate. Then there are trainings and license exams held by Bar Council for barrister and Solicitor Regulation Authority for Solicitor. The Legal Profession under American System doesn’t have such category. They are known as advocates or counsels that includes lawyers, judges, paralegals, and other legal professionals who do both client representation and paper works.
In the United States, the legal profession encompasses lawyers practicing in the private sector, individually or in small to large firms; lawyers employed by the government, corporations, organizations, and legal aid societies; law professors; and judges and related judicial or administrative actors also employed by the government.¹⁴ The students need to first graduate in a degree and join law school for the course of four years, after which they earn a degree of Juris Doctorate and pass the bar exams to be an attorney

5. Provision of Judicial Review: Judicial Review is one of the major differentiating factors between these two systems. As USA practices constitutional supremacy, the courts have the authority to judicially review government activities and check if laws are in accordance with the constitution. While the U.S. Constitution does not explicitly define the power of judicial review, the authority for judicial review in the United States has been inferred from the structure, provisions, and history of the Constitution.¹⁵
Although the English legal system uses judicial review, there is no such thing as judicial review of primary legislation to declare it ultra vires. But after joining the EU, which mandates that its members respect to human rights, the UK passed the
Human Rights Acts of 1998, which provide the court the authority to order the parliament to amend laws that violate them but still cannot declare it ultra vires.

6.    Appointment of Judges: The selection of judges is administered by Judicial Appointments Commission. It is responsible for selecting over 500 people each year for appointment to judicial posts. For superior level judges, the commission selects a candidate and recommends them for the appointment to Lord Chancellor.¹⁶ Whereas in American System, for the federal judges, The names of potential nominees are often recommended by senators or sometimes by members of the House who are of the President's political party. The Senate Judiciary Committee typically conducts confirmation hearings for each nominee.¹⁷ For the selection of state judges, different states follow different methods.. In general, however, approximately half of the States appoint judges and half elect them. Thirty-one States use commission plans to aid the governor in selecting judges. In four States the governor appoints judges without using a nominating commission, subject to senatorial confirmation.¹⁸
Moreover, in English System the judges appointed serve till the age of 75 whereas the judges of American System serve for lifetime.

7. State System and Structure: The English legal system follows Unitary system of government which means there is single central government and it may delegate power and authorities to the local bodies, whereas the American Legal System follows Federal system of government meaning there are two levels of government-federal and state with own autonomous power mentioned in the constitution. Similarly, the English system upholds Parliamentary supremacy with unwritten constitution and on the other hand American system upholds Constitutional supremacy with a written constitution.

8. Appeal: The appeals process in the US Supreme Court and the UK Supreme Court differs slightly. Compared to the American system, the English system's appeal is more limited. If someone wishes to appeal to the UK Supreme Court they must first get permission from the lower court. If the lower court denies permission, they can then request for permission in the Supreme Court, which will then determine whether or not to hear the appeal based on the issue's constitutional and public significance.
On the other hand, to file an appeal in the Supreme Court of USA, one does not require permission. Instead, they must submit a petition of certiorari, explaining why the Supreme Court should appeal the lower court's decision. Not every case is automatically heard by the Supreme Court, only a small number of cases are granted certiorari each year. Certiorari is granted on the basis of court's discretionary power, which allows it to select which cases to hear. Certiorari can only be granted if at least four out of the nine justices agree..

9. Role of the Constitution: In the English legal system there is an unwritten constitution, which means the constitution is spread over statutes, regulations, and customs, making it more flexible. On the other hand, the USA has a written constitution, which means the constitutional provisions are written and published as a single form of book, making it rigid but precise.

Conclusion
To sum up, both American law and English law developed as a result of the influence of common law. English law applied common law as England was the hometown for its development, and American law applied common law because of colonization and the increase in trade and legal learnings from the Inns of England. Resulting from the differences between legal tradition and the changing needs of society, both systems have adapted common law as per its necessity, marking the differences between the systems. However, they still continue to share numerous common characteristics along with the variations.