What if, Friedrich Nietzsche wondered in 1882, a demon came to you and said that you were condemned to live every moment of your life over and over again in an endless cycle of repetition for all time? "Would you not throw yourself down and gnash your teeth," he asked, "and curse the demon who spoke thus?" That, my friends, is what American politics sometimes feels like.

Consider the following. In 1992, Bill Clinton was elected on a wave of hopey-changey elation, a charismatic young president (only 46!) sure to transform the country as the vanguard of a new generation of leaders. Two years later, Republicans took control of Congress, enabling them to make Clinton's life difficult for the rest of his time in office. Then in 2000 they elected one of their own, George W. Bush. Democrats grew fed up and disgusted with Bush, leading to a sweeping win in 2006 in which they took back Congress, enabling them to make Bush's life difficult for the rest of his time in office. Then in 2008 they elected one of their own, Barack Obama. The ensuing backlash delivered Congress back to Republicans, who proceeded to make Barack Obama's life difficult for the rest of his time in office. Then in 2016 they elected one of their own, Donald Trump. And now there is another backlash underway, one that promises to give Congress back to Democrats.

Control of the White House and Congress isn't the only thing that goes around and around; others' fortunes rise and fall with the cycle. In March, Rachel Maddow became the highest-rated show on cable news after years of Fox News hegemony, and with all due respect to Maddow, it isn't because she just started doing something revolutionary. Just as Clinton gave rise to an explosion in conservative talk radio and Bush brought forth the liberal blogosphere (proud to say I was an O.G. blogger), Maddow and other liberal TV talkers are benefiting from another repeated cycle: When there's a Democrat in the White House, conservative media thrive; and when there's a Republican in the White House, liberal media thrive. When your party is out of power you yearn for articulate, informed voices who can tell you what you should be maddest about.

It happens on a policy level, too: The other party moves back into the executive branch and sets about reversing what was done since they were there last, just as the other party did when it took over. Democrats raise taxes on the rich, Republicans cut taxes on the rich. Some things like the Mexico City Policy get turned on and off like a light switch. It has been one of Donald Trump's personal missions to undo everything Barack Obama did to whatever extent he can.

So you might be forgiven for becoming gripped by the cynical belief that there's not much point to the whole exercise. Today's victories will eventually become tomorrow's defeats, and sooner or later you're doomed to see your work undone.

That may be what Senate Majority Leader Mitch McConnell was getting at when he told an interviewer this week that "the decision I made not to fill the Supreme Court vacancy when Justice Scalia died was the most consequential decision I've made in my entire public career." Though McConnell has been in the Senate for 33 years, it's hard to argue.

That's true even though we're talking about a politician whose career has been marked by a single-minded devotion to the goal of attaining and holding power, not because of what he could do with it but simply as an end in itself (a biography of McConnell published a few years ago was appropriately titled The Cynic). McConnell is widely distrusted on the far right of the Republican Party, because they see him as an operator with no deeply-felt convictions, and they're right. Yet McConnell's decision to simply refuse to allow President Obama to fill a Supreme Court seat that was vacated during his term — utterly immoral, bottomlessly cynical though it was — may indeed prove his most lasting legacy. Instead of a Supreme Court with a 5-4 liberal majority it left the court in conservatives' hands, and it's entirely possible that another retirement of one of the court's liberals or the swing vote Anthony Kennedy could leave them with a 6-3 majority. The result will be an overturning of Roe v. Wade as just the appetizer in a right-wing legal smorgasbord that will go on for years or even decades.

That isn't to say that apart from the courts a party can't make lasting change even within the cycle of victory and defeat — but you have to plan carefully. The Obama administration failed to do so in some ways; for instance, they propagated a series of regulations just before leaving office, which enabled Republicans to roll them back through the use of a law called the Congressional Review Act. If Obama had acted sooner before the end of his term, it wouldn't have been possible (or at least it would have required a more cumbersome and time-consuming process). On the other hand, some of Obama's more consequential initiatives, like the Affordable Care Act, have proven more resilient.

And as the experience of the ACA shows, it's possible to move forward even within the action-reaction cycle. Obama signed the ACA, then Republicans tried and failed to repeal it, and now the Trump administration is trying to sabotage it. The result, however, is a public increasingly dissatisfied with the country's health-care system and a Democratic Party embracing universal, government-guaranteed coverage. It may well be that the next time they take power, Democrats will institute a more government-centered system than the ACA, enabled by Republican efforts to make everything worse. Two steps forward, one step back, three more steps forward.

So while the cycle may be eternal, progress is still possible. That doesn't mean it doesn't make you want to gnash your teeth, though.