Four weeks out from the midterm elections, every Democrat, Democratic-leaning independent, and opponent of President Trump and the GOP needs to learn a very simple civics lesson. Protesting with likeminded partisans may feel good. Angrily pounding on the door of the Supreme Court may bring a moment or two of satisfaction. Swearing up a storm on Twitter about the evils of Republican rule may inspire a passing thrill. But none of this will do a thing to change the political dynamic in the country if it isn't followed up by Democratic voters getting themselves to the polls en masse on Election Day.

Voting is the only political act that really matters now.

It would be nice if Democrats could coast to large political gains. There are certainly plenty of signs that they're poised to do quite well on Nov. 6. The party that holds the White House usually loses ground in the midterms. The president is incredibly unpopular and has been from the beginning of his presidency (with his disapproval rating usually beating his rate of approval by more than 10 percentage points). Nearly every poll of the generic congressional ballot over the past year has shown Democrats in the lead, often by substantial margins.

Yet the outcome of the vote remains highly uncertain, and that's only partly a result of the gerrymandering and urban clustering of Democratic voters that systematically favors Republicans. The bigger reason the outcome remains in doubt is the question of turnout. If Democrats feel apathetic, or lazy, or grumpy, or fatalistic, and if they choose to do something other than vote on Nov. 6, they will lose.

That's why the only Democratic message that really matters over the coming weeks is the absolutely crucial importance of their supporters showing up to vote.

The risk that they won't has risen substantially since the pitched battle over filling retired Justice Anthony Kennedy's seat on the Supreme Court ended with Senate confirmation of Brett Kavanaugh. Republicans feel energized, triumphant, and highly motivated to ensure they retain the ability to confirm future appointments to the high court; that is likely to drive GOP turnout higher than appeared likely as recently as a month ago.

Democrats, by contrast, feel demoralized by their inability to stop Kavanaugh even after he was accused of sexual assault and threw a petulant and highly partisan temper tantrum before the Senate Judiciary Committee. In the end, polls showed record low support for his confirmation. And yet Democrats were powerless to stop it.

But giving into despair would end up resulting in a horribly self-fulfilling prophesy for Democrats: Demoralized by losing this latest partisan battle, they would end up acting in a way that ensures they keep right on losing.

If Democrats want to start winning, they don't need to protest, and they don't need to come up with a raft of new insults to hurl at Republicans online and on late-night shows. What they do need is to make absolutely sure that they come out to vote on Election Day, no matter the weather, no matter how many obstacles are placed in the way (like infuriatingly long lines at understaffed inner-city precincts).

This is the difference between the playacting of grand, empty gestures in an ineffective politics-as-theater and doing the hard, unsexy work of potent political action. Like it or not, it is voting that allocates power, and acquiring power is the most minimal precondition of having influence on the political direction of the country. The only hope of the American majority prevailing against the minority faction that currently governs it is for Democrats to act like citizens for a day.

We can and should lament that for most Americans citizenship has been reduced to waiting in a line to cast a ballot on a single day every year or two. When civic expectations are so minimal, it's all too easy to let even this modicum of effort slide — to disconnect from the noisy clamor of politics altogether, to submerge oneself entirely in the private dimensions of life, to assume that one's own puny voice will inevitably end up drowned out by the screaming throngs on the other side, or to think that the defeats of the past and present foretell a future of perpetual futility.

But this is to make a fatal error about the way politics works. A long track record of success can be banished in a day. The memory of a prior setback can propel a party onward toward future victories — provided that people bother to show up and be counted.

Sometimes believing it's worth making such an effort is all it takes to demonstrate that it's true.