“Q: I thought American justice system was based on English common law, not on th

—“Q: I thought American justice system was based on English common law, not on the Roman civil system.”–

Great Question.
Traditional Law + Traditional Law Common to related Tribes = common law. Common law allows traditional law to scale across people as trade increases between them.

Common law, or Traditional European Law, also known as judicial precedent, judge-made law, or case law is the body of law created by judges and similar quasi-judicial tribunals by virtue of being stated in written opinions. In other words common law is EMPIRICAL and DISCOVERED in the resolution of disputes under individual sovereignty, meaning the prohibition on authority (dictators) among european people. This law requires sovereignty, reciprocity, truth, duty, rule of law, and jury, thang, senate, parliament etc.

COMMON LAW between clans tribes etc, also demands CONCURRENT legislation, meaning legislative agreement between clans, tribes, regions, classes, and sometimes even sexes.
Anglo civilization relies on the natural law (soverignty), The empirical Common Law, and the empirical Concurrent legislation, creating a total prohibition on authority. As such our political system is a MARKET for cooperation and NOT a system of rule.
This differs from the french authoritarian continental system of napoleon which is not empirical, but is top down production of law by scholars. Why? English trusted one another and the french were totally untrustworthy as judges. Yes really.

HISTORY
Steppe Herder Formation (sovereignty, reciprocity, truth, duty, rule of law, democracy – the only possible govt for entrepreneurs, pirates, vikings, and raiders.)
… 1) Northern european traditional law (stepp conquest of europe): Corded Ware, Bell Beaker, and forward.
… … 2) Greek traditional law (Greco-Anatolian Souther folk)
… … … Greek Legal Form
… … …. … Roman Legal Form (Italo Celtic central folk)
… … … …. … Roman discovery of the ‘common’ findings in law among many differen european groups.
… … 3) early germanic traditional law (germanic folk)
… … … … … … germanic traditional “common” law
… … … … … … … anglo saxon ‘common law’
… … … … … … … … norman admnistration
… … … … …. … … …. … The anglo constitution
… … … … …. … … …. … … American constitution

Reply addressees: @Lucius_S_Fel1x @NatLawInstitute @vyomaga