The 2018 midterm elections are less than 100 days away. But get ready: The 2020 presidential contest is already gearing up. And Ohio Gov. John Kasich looks more and more like he’s ready to jump into it.

Officially, Kasich is taking a “maybe yes, maybe no” stance. But his strategist, John Weaver, sure is making it sound like Kasich will get to “yes,” telling the Washington Post that the Kasich team will “bring a machete to a knife fight” with Trump.

The White House counters that Kasich’s machete will go unnoticed because “no one” is “showing up to that fight.” Except that Trump is himself drawing spectators to the prospective fight by tweeting about Kasich. And Weaver is very, very good at getting press attention for his candidates (think of John McCain’s Straight Talk Express in 2000).

Can Kasich beat Trump? Unlikely. But if he does it right, he can mercilessly attack him and drive his negatives up further with voters Trump wants to appeal to; force Trump’s team to burn time (the one irreplaceable resource in campaigns) dealing with Kasich; and generally telegraph the message that Trump is weaker with his own party and Republican-inclined independents than he thinks. That could mean Kasich causes Trump to lose the general.

For months now, Trump allies have been pursuing an agenda via the Republican National Committee to make it more difficult for a Trump challenger to rack up delegates in the 2020 primary, should a challenger emerge. The biggest win was securing the role of Trump Ohio boss Bob Paduchik as head of the Presidential Nominating Process Committee.

“ New Hampshire is famed for its voters’ tendency to favor candidates who excel at retail politics. That’s not Trump. But it might be Kasich. ”

That committee can swing the primary calendar in Trump’s direction, set rules allowing the primary winner to take all of a state’s delegates (which would presumably help Trump), and generally make life very hard for any Republican challenger. Rules will be locked down in late 2019, if the 2016 cycle’s rule-setting experience is a guide.

If Trump’s challenger looks likely to be Kasich, you can bet Paduchik will deploy the full arsenal of weapons available to him to boost Trump and harm the still-serving Ohio governor. There is no love lost between Paduchik and Kasich, and that’s setting aside how the president feels about the latter. Paduchik went so far as to get the head of the Ohio GOP replaced in a move that seemed designed to stick it to Kasich, and hard.

The president currently appears popular with RNC members, too—though if the GOP gets crushed by a blue wave in November, that might change. There might then be more support for proportional allocation of delegates in the 2020 contest, and Trump’s support among Republican voters might slip. All that could provide an opening for someone else.

But would that individual be Kasich? He only won one state in the 2016 nominating contest—Ohio. Conservative favorite Ted Cruz won far more. And thus far, it doesn’t appear Cruz is running. It’s also not clear that Trump-skeptical Republicans and Independents would really vote against Trump in a primary.

If a more moderate Democrat makes headway in that party’s contest, where Republicans and Independents can vote in a primary or participate in a caucus, they might decide to take part in the Democratic nominating process instead of backing what might be seen as a futile effort to take Trump down from within the GOP. Of course that’s a big if in the party of Bernie, but it could happen.

On the subject of Sanders, it’s worth considering the example he set in 2016. Remember when he launched his campaign against Hillary Clinton and everyone thought he was displaying the first public signs of dementia or some sort of mental break? How many people look back on the 2016 primary now and think it wasn’t worth Sanders’ time to run?

Sure, he lost. But not by nearly as much as anyone would have expected. And if it weren’t for the superdelegate system, he’d look like even less of a loser. Meanwhile, his vision for the Democratic Party looks like the future, while Hillary’s looks like the past.

And here’s the main point, as regards Kasich and 2020. Sanders weakened Clinton enough for her to lose. He had months of free press coverage that he spent calling Clinton a corporate shill, which did huge damage to her on the left. If that can happen in the Democratic primary against a big and powerful force like Clinton, couldn’t it happen in the GOP, too—especially if Republicans look around the day after Election Day 2018 and see that Trump has cost them votes and potentially control of both chambers of Congress?

Republicans generally do appear more likely than Democrats to get in line with whoever their party leader is and to stick with him until the going gets very, very, very tough. It will take a lot for routine Republican primary voters to bail on Trump in 2020, especially while he keeps hammering on the New York Times, wealthy NFL players, or liberals of whatever stripe is most easily bashed on any given day.

But it’s worth remembering that Trump is not currently in good standing in New Hampshire, a state that Kasich apparently will be visiting this November and which holds the first primary. As of July 2018, Morning Consult polling shows Trump with a 55 percent disapproval rating in New Hampshire and a 42 percent approval rating—not great numbers in a place that is also famed for its voters’ tendency to favor candidates who excel at retail politics. That’s not Trump. But it might be Kasich. Weaver certainly has experience building candidates from zero to at least a half-decent share of the vote there. McCain beat George W. Bush by nearly 20 points there.

Also in Iowa, where voters currently can register as Republican the same day as a caucus, Trump’s approval numbers are not great. Morning Consult had him at 45 percent approve, 51 percent disapprove as of July, and as Trump’s tariffs bite farm country harder, those numbers may drop further.

Ultimately, it’s exceedingly unlikely that Kasich—or anyone else— would ever depose Trump as the 2020 GOP nominee, unless Trump wants to be deposed. The delegate rules plus Trump’s strength with GOP voters plus his campaign war chest almost certainly guarantee that. But like Sanders to Clinton, Kasich could be a major headache for Trump if Trump allows him to be, and if Kasich is determined to be. He could garner significantly more of the vote than observers expect, and like Sanders, he can force attention onto negative aspects of Trump’s record, and that’s how he might ultimately be the guy who kills Trump off electorally.

History bears out this truth: Those who challenge sitting presidents do not win their primaries; but presidents who sustain non-de minimis primary challenges do lose general elections. Just ask Presidents Ford, Carter, and George H.W. Bush. And maybe, in just over two years, President Trump.