History illustrates the point. The Constitution’s speech protections did not emerge fully formed when the nation was founded. During World War I, for example, the Supreme Court upheld long prison sentences for merely criticizing the war. Over many years, anarchists, communists, labor unions and civil rights activists fought for and earned the speech rights we know and take for granted today.

Nor is the First Amendment outmoded. The need for its protections are as urgent as ever. In just the last year or so, my organization, the American Civil Liberties Union, has invoked the First Amendment to defend high school students disciplined for walking out from school to call for gun control, as well as other students penalized for posting pictures of guns on social media; a student newspaper denied funding after publishing a satire of “safe spaces,” as well as fans of a hip-hop band labeled gang members; Milo Yiannopoulos and the animal rights group People for the Ethical Treatment of Animals, both of whom were denied permission to advertise on the subway by the Washington Metro Authority; and anti-Trump as well as pro-Trump demonstrators. We’ve defended flag desecraters, union organizers, and citizens blocked from their representatives’ Facebook sites for their criticism. And that’s just the beginning.

As even this very partial list shows, government officials continue to be tempted to silence people for their views. Some of our clients are liberal, others conservative, but all have been singled out because they have upset those in power.

Not every First Amendment argument is justified, of course. The A.C.L.U. supported the public sector union in the Janus case, for example, saying that charging workers for services that the union is required to provide to them is not a First Amendment violation, any more than requiring people to pay taxes for government policies they oppose. But even if conservatives sometimes win free speech cases they should lose, now is not the time for anyone to dismiss the First Amendment as a tool of conservatives.

Since Donald Trump’s election in November 2016, Americans have been exercising their First Amendment rights to engage in resistance: demonstrating, calling their representatives, associating with like-minded citizens in defense of core values, shedding light on official abuse through the free press, and expressing themselves on social media.

When one party controls all three branches of the federal government, the checks and balances have to come from the people. It’s on us. And it’s the First Amendment that gives us the tools to act — including the rights to speak, associate, petition the government and enjoy a free press.

The fact that conservatives benefit from the First Amendment is not something to bemoan. It is part of the constitutional bargain. It simply means the First Amendment is operating as it should, neutrally preserving the lifeblood of democracy.