Who will succeed Donald Trump as president?

No one knows when President Trump will leave office. Possibly January 2021 when his first term ends; possibly not before January 2025 when a second term would end. Ultimately, however, he will leave office sometime to be succeeded by the next president.

But who will that be? That intriguing question increasingly occupies the attention of politicians from both parties.

Already there is conjecture he may be challenged from within the GOP — an action always fraught with peril for the incumbent party.

Even more speculation has centered on a formidable list of Democratic aspirants. At least two dozen potential Democrats are cautiously assessing their chances in 2020.

But what do we really know about “next presidents” — who they are likely to be, where they come from, their typical backgrounds, and so on.

A general consensus prevails that the next president is likely to differ from the current president in a host of ways, including personality, career background, temperament, and policy preferences.

Think back just to our last 10 or so chief executives.

Trump differs from Obama dramatically on those attributes, but Obama and George W. Bush were hardly soulmates, nor were George W. Bush and Bill Clinton or Clinton and George H. W. Bush.

Ronald Reagan differed from Jimmy Carter strikingly as did Carter from Gerald Ford, Ford from Richard Nixon and Nixon from Lyndon Johnson, ad infinitum.

The next president is a reaction to the last president, if not an opposite type. Voters often look for the anti-incumbent.

One way to identify Trump’s anti-type is to identify the traits voters dislike about him, knowing voters will especially be looking for opposite traits in the next president. A number of national polls have focused on quantifying the reasons people don’t like Trump.

We cite three completed in the last few months as representative, one from Quinnipiac, one from Gallup, and one from Fox News. Their conclusions are similar.

Quinnipiac, surveying Trump’s “positive /negative” ratings on a cluster of character traits, found Trump’s “net negative” ratings highest in traits such as not being “level headed,” not demonstrating “moral leadership,” not “sharing (their) values,” and lack of “honesty, compassion and leadership skills.”

A second poll from Gallup found most Trump dislike rooted in disapproval of his personality and character, while fewer than one in five disapprovals were because of his policies. Like most other polls, Gallup gave Trump high marks on the economy and several other leading issues.

The third poll from Fox News quantified some of the specific reasons people dislike Trump. Some 22% said Trump was “not capable of doing the job / doesn’t know what he is doing.” Incompetence, temperament and racism were the leading causes cited for disliking Trump – while less than one in seven disliked Trump on policy grounds.

Collectively, all three polls concurred that Trump was widely disliked personally (by as many as 2 out of every 3 voters), but many of his policies are not.

This presents Republicans with a baffling quandary. Many voters dislike Trump personally, implying that Trump heading the GOP ticket in 2020 would be a net drag on the national party.

Republicans could try replacing him as the nominee, but historically a serious challenge to an incumbent president has almost always produced general election defeat.

This is the GOP’s cruel dilemma: they may lose with Trump in 2020; they almost certainly will lose without him.

But 2020 is no free throw for Democrats. They first need to find a candidate sufficiently different from Trump that voters feel they have a choice.

Moreover, Democrats cannot run hard to the left or ignore the popularity of many Trump policies. If Democrats forget why they lost in 2016, they will lose again in 2020.

Republicans are running with a flawed candidate; Democrats are running with flawed policies.

Historically, these conditions in the past century helped produce four major third party candidacies — 1992 (Ross Perot), 1968 (George Wallace), 1924 (Robert La Follette), and 1912 (Teddy Roosevelt).

Will the search for the anti-Trump make 2020 the fifth one?