President Trump is now openly attacking the GOP leaders of both the House and the Senate. In tweets Thursday morning, he blamed Senate Majority Leader Mitch McConnell (R-Ky.) for having “failed” to replace Obamacare, and he said both McConnell and House Speaker Paul D. Ryan (R-Wis.) created the current debt ceiling “mess” by using the wrong tactics.

The tweets lay bare tensions that both the White House and McConnell’s office have sought to play down in recent days, after an extensive New York Times piece detailed a strained relationship between the president and the GOP Senate leader, including Trump berating McConnell in a phone call two weeks ago. Although Trump has been known to attack pretty much anybody and this could just as soon blow over, the tweets suggest a looming showdown between Trump and his own party in Congress if it doesn’t deliver on his agenda to his satisfaction.

Congressional Republicans should be very worried. Trump could tear them apart — and he’s already starting to do so.

Despite Trump’s broad and unprecedented unpopularity early in his presidency, he retains a pretty strong hold on his base, with around 75 to 80 percent still approving of him. There are signs that his hold on that base is cracking, yes, but the vast majority of Republicans remain loyal and are following Trump’s lead.

What’s more, a growing body of polling evidence suggests real peril in Republicans being seen as failing or undermining Trump.

Case in point: A new George Washington University Battleground Poll released shortly before Trump’s tweets showed 53 percent of Republicans in districts with Republican members of Congress say their member has not been “supportive enough” of the president. Another 35 percent say their support has been “about right,” and just 4 percent — 1 in 25 Republicans — say their member has been “too supportive.”

In that way, Trump is already tilling fertile soil by attacking the likes of McConnell, Ryan and Sens. Jeff Flake (R-Ariz.) and Dean Heller (R-Nev.). A strong majority of the GOP base thinks their party hasn’t done enough to help Trump, and now Trump is blasting that message far and wide.

That holds true for specific senators as well as the party. The limited polling we have on individual members suggest those who have tangled with Trump have paid a steep price in their personal image ratings.

A poll from Democratic-leaning automated pollster Public Policy Polling this month showed a grim state of affairs for Heller, who initially opposed the GOP health-care bill and drew Trump’s ire before eventually supporting a later version. The PPP poll showed him with a brutal 22 percent approval rating in Nevada, compared to 55 percent who disapproved.

Ditto the other vulnerable Republican senator up for reelection in 2018, Flake, who has been a more vocal Trump critic than Heller. Around the same time, PPP had him at just 18 percent approval in Arizona versus 62 percent disapproval. Again, brutal. The reason? Trump voters are almost completely deserting him, with just 22 percent approving of him and 63 percent disapproving.

PPP has also now released data on McConnell, whom Trump has been needling for weeks. And guess what? His ratings have plummeted thanks to Trump voters, too. Fully 66 percent of Trump voters say they disapprove of him, driving up his overall disapproval rating to 74 percent. Just 18 percent approve.

President Trump and Senate Majority Leader Mitch McConnell's relationship is fraying. (Jenny Starrs/The Washington Post)

We have very limited polling here, and it’s all from one, partisan-leaning pollster. But if those numbers are even close to reality, it suggests Republicans are at significant risk of alienating the base if they don’t fall in line behind Trump and/or succeed for him. Both Flake and Heller now face primary challenges, and seeing how those races poll going forward is going to be extremely telling. If Republicans see Flake and Heller struggling to win renomination, you can guarantee they’ll be scared of opposing Trump going forward.

We need to see more data, but the data we have is starting to paint a picture, and it’s that Trump could tear apart the GOP — and individual members — by pitting himself against them. In fact, it looks like he’s already doing it.