If you look at the trend in Quinnipiac's polling since January, strong approval of the President's job performance has faded in a number of constituencies - including Republicans and whites without college degrees.
The trend among Republicans is a decline of about seven points. Among whites without a college degree, about 10.
It's rare that opinions of people flip 180 degrees in politics. For example, when people are changing their minds about who they'll vote for, there's often a way-station at "undecided" before their candidate choice flips.
Similarly, people are less likely to go from strong approval of what Trump's doing to outright rejection of it; instead, their approval would likely fade a bit first.
That trend appears, too.
Among white women in particular, views of Trump in Quinnipiac polling are hardening.
By the same token, if people are turning against Trump, that would suggest that those who viewed his job performance sceptically in the first place might come to strong disapproval of him.
At the moment, Trump needs all of the support he can get from his base, given the increasing questions about his handling of the investigation into Russian meddling in the 2016 election.
If Republicans on Capitol Hill think his core base of support is wavering, that might make Trump's next few months even less comfortable than they might otherwise have been.
