The 2018 midterm elections are just getting rolling, but 2020 is on the horizon — and a new poll might give President Donald Trump something to sweat about. According to a Politico/Morning Consult survey released on Wednesday, just 36 percent of voters say they would vote for Trump over a generic Democratic candidate in the next presidential election, while 44 percent would pick the Democrat. One-fifth of voters still aren’t sure.

While presidents typically don’t face a tough road to get their party’s nomination, six in 10 voters, including 38 percent of Republicans, say they’d like to see Trump get a Republican challenger in 2020. But it’s not clear whom they’d like to see take on the former reality television star. (And it looks like it is not going to be Vice President Mike Pence.)

If it comes down to Trump and Pence, more Americans would prefer Trump keep the job of president over Pence. Thirty-four percent of respondents said they would have Trump, and 23 percent said they prefer Pence. (Forty-three percent said they didn’t know or were unsure.)

It appears Pence, once a conservative darling, is falling out of favor with the GOP. Sixty-four percent of Republicans say they would prefer Trump as president, and only 19 percent Pence. In August 2017, 58 percent of Republican voters said they preferred Trump and 28 percent said Pence.

Voters aren’t loving Trump right now — but they didn’t when he was elected either

As Politico notes, just because Trump isn’t particularly popular among voters doesn’t mean he couldn’t win. That’s what happened in 2016, when 38 percent of voters had a favorable opinion of him in exit polls and 61 percent said he wasn’t qualified to be president. Trump lost the popular vote to Hillary Clinton by about 3 million votes, but he did win the Electoral College.

Of course, there were some specific circumstances in 2016 that are unlikely to be repeated in 2020 — both Trump and Clinton were historically unpopular candidates, and there was a surge in third-party voting for Green Party candidate Jill Stein and Libertarian candidate Gary Johnson. And, of course, there was the now-infamous letter from then-FBI Director James Comey announcing that the Clinton email investigation would be reopened days before the election.

But Trump does better than a generic Republican against a Democrat in a theoretical 2020 matchup, according to Wednesday’s poll. Twenty-seven percent of voters say they would support a Republican candidate who isn’t Trump over a Democrat, while 40 percent say they would rather have the Democrat. One-third of voters aren’t sure.

Trump has been ramping up 2020 campaign efforts essentially since day one — he filed paperwork for his reelection the same day he was inaugurated. He has kept up fundraising, ending 2017 with $22 million in cash, and he has had multiple campaign rallies across the country.

In February, he named data guru Brad Parscale to be his reelection campaign manager and launched a new fundraising initiative to benefit his campaign and the Republican National Committee. It rewards donors who “bundle” contributions, meaning they get donations from others.

On Wednesday, Trump’s reelection campaign announced that veteran Republican strategist Chris Carr would come on board as political director. Carr’s job will be, in part, to spearhead the Trump reelection campaign’s engagement in the 2018 midterms and support for pro-Trump, or, as Parscale put it in a press release, “America First,” candidates.