President Trump’s most important domestic measure, the Save America Act, has run into the Senate’s filibuster wall. Putting aside the question of the merits or necessity of the bill, it is a real question whether the American republic even exists if that wall stands. A century ago, G. K. Chesterton wrote that, “The liberty to make laws is what constitutes a free people.” So how can Americans today be free when no law can be passed unless 60 senators agree? If nothing can be done unless both parties agree, then nothing will be done—at least nothing democratic.

The Constitution does not require a super-majority of senators to pass legislation on to the president for his signature. A simple majority is enough. The Constitution only requires a supermajority to ratify treaties, override presidential vetoes, and convict those officials or judges impeached by the lower House. Yet under the current Senate rule, 60 votes are required to formally end debate (called “cloture”) and bring legislation passed by the House of Representatives to a vote. That is why the Senate has not even voted on the Save America Act.

The traditional filibuster, also called the “talking filibuster” to distinguish it from the current mess, the so-called silent filibuster, is very different. It is merely aparliamentary delaying tactic, designed to draw the nation’s attention to a matter and give time for senators to change their minds. It does not prevent the passage of legislation. It merely opens and prolongs the debate. Anyone who has watched the film Mr. Smith Goes to Washington can see the real thing in dramatic action. But that is not how it operates today.

Under the silent filibuster, senators need not hold the floor and talk continuously as Jimmy Stewart’s character did in that beloved film. They merely need to invoke the word “filibuster,” and it averts a vote indefinitely. The practical effect is the same as if the Constitution had been amended, with the crucial difference that the Senate could suspend, modify, or abolish it at any time. Doing so is being called the “nuclear option,” no doubt to scare people.

The late William J. Quirk, a professor of law at the University of South Carolina, and a long-time contributor to this magazine, wrote a book arguing that we are no longer being governed according to our written constitution. Rather we live under an unwritten one. He called it a “convention” and, in keeping with British usage, defined it as “an unwritten understanding or agreement among the [leaders] of the three branches [of government] arbitrarily rearranging their constitutional powers.” The senatorial filibuster proves his argument.

If it is unconstitutional, it is also un-republican, for it amounts to a minority veto. As Alexander Hamilton wrote, republican government “requires that the sense of the majority should prevail.” He explains that “to give a minority a negative upon the majority, which is always the case where more than a majority is requisite to a decision is, in tendency, to subject the sense of the greater number to that of the lesser.”

So why is it even there? Perhaps a clue lies in how it has been used. The last time the Republicans held the presidency and both houses of Congress was 2017-18, in the aftermath of Donald Trump’s victory over Hillary Clinton. The Republicans had a 52-48 majority in the Senate, and a 241-194 majority in the House. So what did they do? They did lift the filibuster wall for Supreme Court nominees (the Democrats having done so in 2013 for lower federal court nominees), but they retained it for legislation. Twenty-eight Republican Senators, and 32 Democrats, even signed a letter co-authored by Sen. Susan Collins (R-Maine) and Chris Cooms (D-Del.) calling on then-Senate Majority Leader Mitch McConnell to retain the 60-vote filibuster threshold. We can understand why Democrats would want to preserve it since they were in the minority. But the Republicans? Why would they negate their own power?

Now, eight years later, it is happening again. The day after Trump won back the presidency and his party retook the Senate, McConnell (then the Senate minority leader) announced, “The filibuster will stand.” And under his successor, new Majority Leader John Thune of South Dakota, it has stood. This time, only a handful of Republican senators are willing to publicly defend retaining it, but the effect is the same. America First legislation has no chance of becoming law as long as this prevails.

Senators have given various reasons over the last 10 years for keeping it. They have said that it fosters bipartisanship, consensus, cooperation, and compromise; that it averts erratic swings in policy, and protects the rights of the minority. They have also warned of the danger that the other party, when it controls all the levers of power, will abuse that power without the filibuster. We are warned that Democrats will pack the Supreme Court with leftist judges and add two new blue states to the Union.

The late Walter Karp believed that collusion, not competition, was the real governing principle of our two-party system. The professionals of both parties have a shared interest in preventing insurgent groups from taking their places, and they are willing to lose an election (even by allowing the other side to cheat) to prevent that. The parties, he noticed, are funded by the same interests, and actual policy differences between them are slight.

The filibuster protects both parties from enacting measures popular with their constituents but unpopular with those who really matter, such as donors. Senator Thune’s comments in February about why he won’t lift the filibuster are revealing. “In the end, you’re a family, and this is a team, and we need the team to succeed, and you have differences of opinion along the way, and you don’t always get what you want.” True, but you get what you need, as Mick Jagger said.  And what Thune clearly needs is both to keep the filibuster and defeat the Save America Act. That’s how he measures the “success” of his “team.”