It is certainly true that not all founders were Calvinists, but many of them were

An interesting essay, Calvinism and American Independence by Mark David Hall. The opening argument:

Professor Allen writes: “Dr. Hall points out that 50-75% of Americans during the founding era were Calvinists … [b]ut once again, ‘the founders’ and ‘the American people’ are not at all the same thing.” It is certainly true that not all founders were Calvinists, but many of them were, and they drew from a tradition of political reflection that encouraged them to actively resist tyrants.

Let’s begin by considering just one Reformed founder, Connecticut’s Roger Sherman. Sherman was the only statesman to help draft and sign the Declaration and Resolves (1774), the Articles of Association (1774), the Declaration of Independence (1776), the Articles of Confederation (1777, 1778), and the Constitution (1787). He served longer in the Continental and Confederation Congresses than all but four men, and he was regularly appointed to key committees, including those charged with drafting the Declaration of Independence and the Articles of Confederation. At the Constitutional Convention, Sherman often outmaneuvered Madison and, according to David Brian Robertson, the “political synergy between Madison and Sherman … may have been necessary for the Constitution’s adoption.”[i] He was also a representative and senator in the new republic where he played a major role in drafting the Bill of Rights. And unlike many of the more “Enlightened” founders favored by Professor Allen, Sherman never owned a slave, and he co-authored a law that put slavery in Connecticut on the path to extinction.[ii]

American patriots drew from a rich and deep tradition of Calvinist thought concerning when tyrants may be justly resisted. Traditionally, many Christians understood Romans 13 to prohibit active resistance to tyrants. Reformers rejected this approach and developed a resistance ideology unlike anything ever seen on a widespread level in Christendom. John Calvin (1509–1564), one of the most politically conservative of the Reformers, contended that in some cases inferior magistrates may resist a tyrant. However, contemporary and later Calvinists including John Knox (1505–72), George Buchanan (1506–82), Samuel Rutherford (1600–1661), Theodore Beza (1519–1605), David Pareus (1548–1622), Christopher Goodman (1520–1603), John Ponet (1516–1556), and the author of Vindiciae Contra Tyrannos argued that inferior magistrates must resist unjust rulers and even permitted or required private citizens to do so.[iii] Note that all of these men were advocating active resistance to tyrants well before John Locke published his Second Treatise on Government.

John Adams was raised in the Reformed tradition, but as an adult he was neither a Calvinist nor an orthodox Christian. But he acknowled the influence of the Reformed tradition. In 1787, he wrote that John Ponet’s Short Treatise on Politike Power (1556) contains “all the essential principles of liberty, which were afterwards dilated on by Sidney and Locke.” He also noted the significance of Stephanus Junius Brutus’ Vindiciae Contra Tyrannos.[iv] Later in life, Adams wrote: “I love and revere the memories of Huss, Wickliff, Luther, Calvin, Zwingli, Melancton, and all the other Reformers, how muchsoever I may differ from them all in many theological metaphysical & philosophical points. As you justly observe, without their great exertions & severe sufferings, the USA had never existed.”[v]

Well worth reading the whole piece.