Senator Bernie Sanders joins former Vice President Joe Biden and Senator Elizabeth Warren onstage before the start at the 2020 Democratic U.S. presidential debate in Houston, Texas, U.S. September 12, 2019.

President Donald Trump remains remarkably unpopular but he'll have at least one valuable asset in his 2020 reelection bid: a Democratic opponent.

That becomes clear in the latest NBC News/Wall Street Journal poll. A 58% majority of registered voters express unease about voting for Trump, but slightly more say the same about Joe Biden and Bernie Sanders, while Elizabeth Warren fares only slightly better.

"Democrats want a referendum on Trump, and Republicans want it to be a choice," says Democratic pollster Peter Hart, who conducts the NBC/WSJ survey with Republican counterpart Bill McInturff. "Therein lies the rub."

Trump's overall standing remains underwater, as 45% of registered voters approve his job performance and 53% disapprove. And fully 69% say they dislike him personally – far more than ever said so of predecessors Barack Obama, George W. Bush, Bill Clinton, George H.W. Bush and Ronald Reagan.

Yet leading Democratic prospects to challenge him face public opinion hurdles of their own. Roughly one-third of registered voters express comfort or enthusiasm about backing Biden, Warren or Sanders, while one-fourth say the same of Pete Buttigieg and Kamala Harris.

In each case the share of voters with reservations about those Democrats is significantly larger. Nor has recent news about Biden, the Democratic frontrunner, helped; 36% say it has made them less confident in him, while just 8% say it has made them more confident in the former vice president.

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The same proportion has grown less confident lately about Trump. But the Republican incumbent continues to benefit from a solid economy, even if voters remain split on how much credit he deserves.

Despite recent jitters over the possibility of recession as soon as next year, 39% of voters say the economy is getting better while 42% see it staying the same. Just 18% see the economy getting worse.

About half of voters, 46%, say the economy has improved and Trump deserves at least some credit for that. That compares to 51% who say the economy either hasn't improved or that it has and Trump does not deserve much credit.

One question hanging over the general election contest is how much the eventual Democratic nominee embraces specific policy views less popular than Trump's. Some widely shared Democratic stances, such as legal status for immigrant "dreamers" and eliminating tuition at state colleges and universities, command large majority support.

Others do not.

The 62% majority opposed to providing government health care to undocumented immigrants, for example, exceeds the 56% opposed to Trump's call for a wall along the U.S.-Mexico border. The 56% opposed to eliminating private insurance as part of a new "Medicare for All" program exceeds the 52% opposed to Republican calls for repeal of Obamacare.

The telephone poll of 900 registered voters, conducted Sept. 13-16, carries a margin for error of 3.27 percentage points.