You don’t have to look for a poll confirming President Trump’s lock on the Republican Party. He maintains over 80 percent approval in most surveys; Republicans generally back his positions whatever the topic (e.g., the Russia investigation is a witch hunt, the tax cut is glorious, Obamacare is horrible). However, supporting a president under constant attack by their political enemies is not the same as picking him for their nominee a second time, according to at least one poll.
A Politico/Morning Consult poll reports:
Just 36 percent of [all] voters say they would vote for Trump over a generic Democratic candidate in 2020, compared with 44 percent who would pick the Democrat, the poll shows. One in five voters, 20 percent, are undecided. . . . Overall, a 60 percent majority of voters think Trump should be challenged in the 2020 primaries, compared with 26 percent who don’t think so. Among Republicans, there is some appetite for a Trump primary challenger: 38 percent think someone should run against him, but half do not think so.
That might not be hugely encouraging for a GOP challenger — although 50 percent of the party wanting no challenger is hardly anything for Trump to brag about — but the midterms may considerably improve a challenger’s prospects. A wipeout for Republicans might well make primary voters, not to mention activists and donors, nervous about risking both the presidency and Congress in 2020.
Moreover, in the abstract, Republicans take Trump’s side in the Russia investigation. However, when they have a concrete, detailed report from Robert S. Mueller III that may recommend impeachment or suggest indictment is appropriate after he leaves office, his supporters may get nervous. By 2020, Paul Manafort’s trial will be in the rearview mirror; Trump will either have consented to an interview with Mueller, taken the Fifth (setting off a political firestorm) or be fending off a subpoena; Michael Cohen and/or Roger Stone may have been indicted or have flipped by then; and a whole lot more will be known about Trump’s finances.