They lost the fight over the Constitution. But the losers won the most beloved part of it, because half of what Americans cherish exists only because the Anti-Federalists demanded it.
The Anti-Federalists were those who opposed ratifying the Constitution as written, fearing it created a national government too strong and too distant, with no guarantee of individual rights. Writing under pen names like Brutus and the Federal Farmer, they warned of a new tyranny replacing the old.
Their central objection was the missing bill of rights. The proposed Constitution listed government powers but not citizen protections. Without written guarantees, the Anti-Federalists argued, nothing would stop the new government from crushing liberties like free speech and a fair trial.
They lost the main battle. The Constitution was ratified in 1788. But they extracted a price: several states ratified only on the explicit promise that a bill of rights would be added immediately.
That promise was kept. James Madison, originally a skeptic, drafted and pushed through the first ten amendments, ratified in 1791. The Bill of Rights, the part of the Constitution Americans quote most, is the Anti-Federalists' lasting victory in defeat.