Political journalism generally fails to answer the most important question.

We wind up talking about what the politicians in the close races want to talk about. And sometimes politicians in close races want to talk about total nonsense, or there are important issues that neither candidate in a close race really wants to talk about. So then you end up with a million dissections of exactly what Democrats’ odds of winning the House of Representatives are but very little sense of why it matters.

So I’m going to try to explain it.

The caravan stakes are nonexistent

The New York Times and the Washington Post have, following the White House’s editorial direction, produced more than 115 stories, of which 25 landed on page A1, about the “caravan” of asylum seekers from Honduras and Guatemala.

Reasonable people can disagree about how important the caravan phenomenon is, but what’s been generally obscured by coverage is how low the stakes are here. Congressional Democrats don’t have any caravan-related legislation that Republicans have been blocking and that will pass if Nancy Pelosi becomes speaker. And Republicans haven’t managed to get together the votes in the House to pass any immigration legislation, so picking up an extra Senate seat or two isn’t going to change anything.

Trump is going to do whatever he’s going to do, and the election outcome isn’t going to materially change that.

If Republicans hold the Senate

Some real stakes are that if the GOP holds the Senate, Bob Corker, Jeff Flake, and John McCain will all be replaced by Trumpier senators.

That’s going to mean Trump will have a freer hand to fire Cabinet officials he’s annoyed with and replace them with other people. That means more politicization of the Department of Justice and possibly the shutdown of the Mueller investigation.

Another important point is that while Trump has appointed a lot of circuit court judges, he’s mostly been replacing Republicans who are taking the opportunity to retire. As time passes, however, more Democratic appointees will roll off the bench, so the Trump impact on the judiciary will grow.

If Republicans gain Senate seats

Right now, Lisa Murkowski and Susan Collins hold the balance of power in the Senate, and they opposed Affordable Care Act repeal.

John McCain’s dramatic last-minute intervention is what we remember, but that’s precisely because Murkowski and Collins were more consistent opponents. McCain’s vote ceased to be pivotal because of Doug Jones’s election, so the great ACA debate remains stuck even after McCain’s death. If the GOP gains a net of two Senate seats, then Murkowski and Collins won’t be pivotal and ACA repeal is back on the table. But of course they’d need the House too.

If Republicans hold the House

One key thing here not on policy is that if the GOP unexpectedly holds the House, that will be taken as a vindication of the political strategy of racial fearmongering that Trump ended the campaign with and that this form of spiteful, exclusionary nationalism is the true soul of the American people. Note that this will be true even if the GOP loses the popular vote by 4 points (even more than Trump lost by) because, thanks to gerrymandering, losing by 4 is enough for a majority.

In policy terms, Republicans will move a regressive tax cut, and they’ll seek to partially offset it with cuts to Medicaid, SNAP, and other means-tested assistance programs. They’ll also probably finish the job of repealing the Affordable Care Act.

If Democrats take the Senate

This looks unlikely, but the policy consequences would be enormous. A Democratic-controlled Senate would constrain Trump’s ability to replace his own executive branch appointees, which in turn would meaningfully reduce his ability to continue politicizing the Justice Department and eroding the rule of law.

From a “norms and governance” standpoint, the Senate is a much bigger deal than the House for this reason. A Democratic Senate would also either slow the pace at which Trump confirms judges or (given Trump’s weak historical ties to the conservative movement) perhaps prevail upon him to put a more balanced slate of appointees together for the sake of letting him claim to be breaking records. This would, again, be a huge deal. The odds of a Democratic Senate are low, but it would set the Trump administration on a very different trajectory.

If Democrats take the House

The GOP legislative agenda is dead if there’s a Democratic House, and it’s possible some kind of bipartisan infrastructure bill gets done. There will also be a lot of interbranch tension as Democrats issue subpoenas and the White House fights back. The House has fewer institutional leverage points than the Senate, so this will be less about being able to actually halt Trump from doing things than about trying to shed light on abuses. But expect tons of legal wrangling.

The other thing about this is that, especially because GOP donor class bills will stand no chance of passing, the political agenda may be even more occupied by immigration issues since that’s what Trump likes to talk about. And even though Trump and Democrats have very different ideas on immigration, they do both want changes to immigration law, so they actually have something to talk about. One could spin an optimistic grand bargain scenario here, but after two years of watching the Trump administration in action, it seems really unlikely to me that he wants a bargain — he wants to fight about immigration.

This is an abbreviated web version of The Weeds newsletter, a limited-run newsletter through Election Day, that dissects what’s really at stake in the 2018 midterms. Sign up to get the full Weeds newsletter from Matt Yglesias, plus more charts, tweets, and email-only content.