Ages ago, at the beginning of 2020, the vote of Sen. Mitt Romney (R-Utah) to impeach President Trump made him the lonely exception that proved the most important political rule for a Republican senator: Unless you want to see yourself flagellated on Twitter, your electoral prospects dimmed and your clout with the Republican Party vastly diminished, avoid President Trump’s ire.

But the GOP’s do-no-harm-to-the-president rule is being disregarded with some regularity in the lead-up to the presidential election, in subtle and unsubtle ways. Here’s what we’ve seen since the coronavirus pandemic hit:

  • Lisa Murkowski (Alaska) said this summer that she was struggling with whether to support Trump.
  • Susan Collins (Maine), in a very tight reelection race that could decide the Senate majority, said she won’t support his latest Supreme Court nominee before the election.
  • Martha McSally (Ariz.), also in a tough race, refused to say at a recent debate whether she’s proud of her support for Trump.
  • Senate Majority Leader Mitch McConnell (R-Ky.), leading in polls for his reelection, said this month that he hasn’t gone to the White House over concerns about their safety measures in a pandemic.
  • Ben Sasse (Neb.), an occasional Trump critic, told constituents last week what he really thought of Trump. (“The United States now regularly sells out our allies under his leadership, the way he treats women, spends like a drunken sailor.”)
  • John Cornyn (Tex.), also up for reelection, this weekend compared the GOP’s relationship with Trump to a bad marriage. (It’s “maybe like a lot of women who get married and think they’re going to change their spouse, and that doesn’t usually work out very well,” he told the Fort Worth-Star Telegram editorial board.)

Trump has slammed some of these people on Twitter in the past few weeks, but it doesn’t seem to have reverberated like it did near the beginning of his presidency, when former GOP senators Jeff Flake and Bob Corker spoke out against the president only around the same time they decided to retire rather than risk voters’ wrath.

The senators who have stuck it out and are now up for reelection in 2020 still don’t want to get on Trump’s bad side. But increasingly they have no choice. Those on the ballot with him are being forced to choose the voters they’ll need in November, and less and less of them support Trump than in 2016.

Republican voters in 2020 appear to be splitting into two distinct groups: a dedicated base that loves Trump’s culture wars, and a group that has tended to vote GOP more for economic reasons than social.

Polls and focus groups suggest that this second group is being turned off by the president over his handling of the coronavirus pandemic, but also his handling of race relations this summer, and four years of nonstop controversies and drama that have simply exhausted many Americans. Trump’s economic accomplishments for his party — rolling back government regulations, passing a tax bill — don’t seem to be resonating in comparison to everything else that’s going on.

As The Washington Post’s Paul Kane notes, it’s tough to be a Senate Republican aligned with Trump, too. In Iowa, Sen. Joni Ernst (R) appears to be losing suburban voters’ support in her reelection campaign as she sticks with the president.

This situation is different from when some in the party left him in 2016 weeks before the presidential election. Then-House Speaker Paul D. Ryan (R-Wis.) told his colleagues that they could ditch Trump to try to save their jobs. Breaking with Trump was motivated by a particular controversy — Trump’s “Access Hollywood” tape — and a sense that Trump couldn’t win.

Trump has not been willing to campaign more toward the center to help them. Getting covid-19 hasn’t given him more respect for public-health advice that polls show most Americans support, such as wearing masks. And over the weekend at a rally in Michigan, he said there was “something beautiful” about protesters in the wake of George Floyd’s death being “pushed around.”

We could see more Republicans break from the president in these final two weeks of the campaign. Of the 14 most competitive Senate seats this November, 12 are held by Republicans. They’re mostly in states that have traditionally leaned Republican — we talked about Arizona and Iowa and Texas, but also South Carolina, Kansas, Georgia and Montana.

In a more normal election season, being in their own territory would be helpful for Senate Republicans. But many of these are the states where the party split over Trump is most pronounced.

For example, Trump won Montana by 20 points in 2016. A recent New York Times-Siena College poll had Trump up by just seven points in that state, and the Senate race between Sen. Steve Daines (R) and Democratic Gov. Steve Bullock is basically tied in polling.

Trump won South Carolina by 14 points in 2016, and a New York Times-Siena College poll has his lead nearly cut in half, to eight points. Sen. Lindsey O. Graham (R-S.C.), one of the most well-known Trump allies on Capitol Hill, is in a surprisingly close reelection race against Democrat Jaime Harrison. That same poll had Graham leading by six points; others in recent weeks had the race tied.

It’s tough to predict which Senate Republican might speak out next against the president, even nominally. (None of what senators have said so far probably will satisfy their critics, who argue that Republicans in Congress have let Trump get away with all but murder.)

But it’s undeniable that we’ve reached a moment where Republican Party leaders are more willing to criticize Trump than at any time since right before his 2016 election. And that’s not the status quo for a party that has come to be defined these past four years by its loyalty to Trump.