George Washington has a monument; Jefferson has a memorial; and even James Buchanan has a spot in Washington, D.C., dedicated to his legacy. But there’s no slab of marble in honor of James Madison.

Yesterday was James Madison’s birthday, so today let us then remember his legacy as the father of our Constitution.

Madison conceived the basic outline of the Constitution before the Constitutional Convention even met. He came to the Convention steeped in the histories of ancient republics, well-versed in the political theory of the ages, and prepared with a plan for the new government. The Convention took an oath of secrecy but did not remain shrouded in mystery, because we have Madison’s detailed notes.

After the Constitution was drafted, Madison teamed up with Alexander Hamilton and John Jay to write the Federalist, which in Jefferson’s words was “the best commentary on the principles of government, which ever was written.” The key phrases we associate with the Constitution—federalism, checks and balances, and the separation of powers—appear not in the document itself, but in the Federalist. It’s James Madison who writes, “If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary.” And Madison who concludes: “In framing a government which is to be administered by men over men… you must first enable the government to control the governed; and in the next place oblige it to control itself.”

Once the new Constitution was implemented, Madison served in Congress. As chairman of the House conference committee on the Bill of Rights, he was the principle author. This position enabled him to look after a cause dear to him throughout his political career—religious liberty. Madison’s original draft of the First Amendment read: “the civil rights of none shall be abridged on account of religious belief or worship… nor shall the full and equal rights of conscience be in any manner, or on any pretext, infringed…” Though somewhat less expansive in its protections, the final version bears Madison’s mark: “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof.” Joe Loconte argues that thanks “largely to Madison, free exercise replaced toleration as the national standard for protecting religious liberty.”

Madison is sometimes invoked as the father of nullification, too. But, as Christian Fritz expertly lays out, Madison may deny paternity. Madison maintained that single states lacked constitutional authority to nullify national laws. But interposition refers to various state actions designed to arouse public opposition, challenge federal actions, and ultimately change or stop the objectionable action. Through public opinion, protests, petitions, or even the state legislatures acting as an instrument of the people, the interposer would focus attention on whether the government’s actions were permissible under the Constitution. Though often confused with nullification, Madison’s understanding of interposition was consistent with the Constitution and encouraged states and citizens to remain vigilant against federal encroachment.

We don’t need a slab of marble to remember James Madison. Instead, we have the Constitution that created the framework for ordered liberty and more than 200 years of stable, peaceful republican government. We have the Bill of Rights that singles out specific individual liberties that all Americans possess, especially the right to religious liberty. And, most importantly, we have his legacy on how to defend this document.