Conservative Charlie Sykes argued Thursday that left-leaning Democratic candidates like Sen. Bernie Sanders Bernie SandersKenosha will be a good bellwether in 2020 Biden's fiscal program: What is the likely market impact? McConnell accuses Democrats of sowing division by 'downplaying progress' on election security MORE (I-Vt.) would almost “guarantee” another victory for President Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE in the 2020 election.

“There are candidates that if they nominate, I think would almost guarantee Donald Trump’s re-election,” Sykes, the editor-in-chief of conservative magazine The Bulwark, told Hill.TV’s Buck Sexton and Jamal Simmons about the emerging Democratic candidates for the presidential race.

“I think if they nominate Bernie Sanders, you’re going to see another four years of Donald Trump,” he added.

The Democratic primary race is already shaping up to be a crowded field.

Sanders, along with former Vice President Joe Biden Joe BidenSenate Republicans face tough decision on replacing Ginsburg What Senate Republicans have said about election-year Supreme Court vacancies Biden says Ginsburg successor should be picked by candidate who wins on Nov. 3 MORE, is one of the many candidates likely to run for the party’s nomination. So far, nine Democrats, including Sens. Kamala Harris Kamala HarrisThe Hill's Campaign Report: Trump and Biden vie for Minnesota | Early voting begins in four states | Blue state GOP governors back Susan Collins Kamala Harris: Black Americans have been 'disproportionately harmed' by Trump Biden town hall draws 3.3 million viewers for CNN MORE (Calif.) and Elizabeth Warren Elizabeth WarrenBiden's fiscal program: What is the likely market impact? Warren, Schumer introduce plan for next president to cancel ,000 in student debt The Hill's 12:30 Report - Presented by Facebook - Don't expect a government check anytime soon MORE (Mass.) and former Housing and Urban Development Secretary Julián Castro, have officially announced their presidential bids.

Sykes, who has long advocated against Trump, said Republicans on the other hand don’t have nearly as many options. So far, no Republicans have announced their intention to run against the president.

Even though the conservative editor acknowledged that Trump will likely be the GOP nominee in 2020, he hopes that there are at least some alternatives for the sake of party.

“I really hope for the sake of the Republican Party that there’s an alternative,” he said. “I mean, I understand what the polls are; they’re very, very clear,” he said, noting that the president’s approval rating has remained strong among his Republican base even amid the longest government shutdown in U.S. history.

Trump’s overall approval rating has plummeted amid the partial government shutdown. But the latest polls suggest that his favorability has remained strong among his supporters.

According to a new survey by the Associated Press-NORC Center for Public Affairs Research, 34 percent of Americans overall approve of Trump’s job performance. That’s down from 42 percent from the previous month.

Trump’s approval rating among Republicans, meanwhile, has nevertheless stayed close to 80 percent, including in the AP poll.

—Tess Bonn