President Trump is strengthening his grip on the Republican Party as they head into the heat of an election season that Democrats want to make a referendum on Trump and his handling of the coronavirus crisis.

Trump flexed his muscle on Capitol Hill last week by scuttling bipartisan legislation to extend the intelligence surveillance powers that had passed the Senate easily and was expected to pass the House.

Once Trump threatened on Wednesday to veto the measure, Republican support in the lower chamber fell away quickly, forcing Speaker Nancy Pelosi (D-Calif.) to pull the bill from the schedule.

The president sent a warning a week ago that disloyalty will be punished by scorching former Sen. Jeff Sessions (R-Ala.) on Twitter. Sessions is running to win back an Alabama Senate seat.

Trump lambasted Sessions, his former attorney general, for recusing himself from the investigation into alleged collusion between Trump advisers and Russia. The president also gave Session’s primary opponent, former Auburn University football coach Tommy Tuberville, a ringing endorsement.

“He’s gotten increasingly bold in asserting his will in the Republican Party,” said Vin Weber, a GOP strategist. “He doesn’t seem reserved about exercising influence. There’s just no question the party is dominated by the president and his supporters and his backers and his organization.”

Trump is facing huge challenges in his presidency, from the coronavirus and an economic crisis to the violence that broke out in cities across the country over the weekend sparked by the death in Minneapolis police custody of George Floyd. 

Trump's bellicose tweets about looting leading to shooting has earned criticism from Democrats and Republicans alike, showing once again that GOP lawmakers will break with the president when they think he goes too far.

“Those are not constructive tweets, without any question,” Sen. Tim Scott (R-S.C.) said Sunday during an appearing on Fox News Sunday. 

Yet overall, Republicans are reluctant to break with the president and are in many ways taking their cues from him. 

“It’s not a Washington phenomenon, it’s a grass-roots phenomenon,” Weber said. “His support is out in the countryside, in the Republican Party, and I think if not for that there would be at least some brake on the president’s actions in Washington. But there’s not because [lawmakers] go back home and find the party wants to back the president almost without restraint."

“I think that’s going to be become more the case, not less the case, as we go forward,” he added. 

Another sign of Trump’s imprint are the investigations moving forward in the Senate, where the Judiciary Committee and the Homeland Security and Governmental Affairs Committee are now probing the origins of the FBI investigation of Trump’s 2016 campaign, Hunter Biden’s business dealings in Ukraine and the prosecution of former Trump national security adviser Michael Flynn.

These are all subjects that many Senate Republicans had shown little appetite to delve into, but they are now moving forward in large part due to Trump.

Senate Judiciary Committee Chairman Lindsey Graham (R-S.C.) announced on May 18 that his committee would vote in June on authorizing a subpoena covering an array of former Obama administration officials, including former FBI Director James Comey, former Director of National Intelligence James Clapper and former CIA Director John Brennan.

Graham made his announcement days after Trump tweeted that Congress should call on former President Obama to testify “about the biggest political crime and scandal in the history of the USA,” referring to the FBI’s investigation of his 2016 campaign. The president singled out Graham, tweeting, “Do it @LindseyGrahamSC, just do it. No more Mr. Nice Guy. No more talk!”

Graham, who is up for reelection this year, has declined to ask the former president to testify, but he’s moved forward aggressively with the probe.

Weber said the unsuccessful effort by Democrats to remove Trump from office after impeaching him only solidified the president’s support among Republicans.

“The whole effort to impeach the president by the Democrats has strengthened him in his ability to go to his own base and say, ‘My detractors have been lying to you and the country the last three years,’” he said.

Trump’s approval rating in the Gallup tracking poll hit the highest point of his presidency, 49 percent, during the Senate impeachment trial in January. It has since hit 49 percent in four subsequent Gallup polls.

“Trump’s approval numbers within the party are through the roof and have been through the roof since we’ve tracked him,” said Chip Saltsman, a Republican strategist.

“Trump actually does stuff as the titular head of the party, not just show up on the convention stage,” he added. “He’s not afraid to get involved in primaries for his friends or be against people he doesn’t like and that what we’ve really seen as different than most."

“Most of the Republican presidents we’ve seen would be hesitant to get in and support the people that supported them earlier,” Saltsman added.

Trump will, he said, and he’ll put his “name and endorsement and money and Twitter followers” behind those he wants to help.

Saltsman pointed to the role Trump played in helping Florida Gov. Ron DeSantis and Georgia Gov. Brian Kemp win competitive primaries and then general elections in 2018.

DeSantis was trailing his Republican opponent, former Rep. Adam Putnam, by double digits in the polls until Trump endorsed him.

On the other side of the coin, Trump’s public attacks on past critics such as former Sens. Jeff Flake (R-Ariz.) and Bob Corker (R-Tenn.) drove down their popularity among Republican voters, and they both eventually retired from Congress.

Trump’s job approval rating among Republicans stood at 92 percent in the last Gallup tracking poll conducted from May 1 to May 13. It has bounced between 91 percent and 94 percent since mid-January, according to Gallup.

The president has asserted his power over fellow Republicans from the macro to the micro level.

His nominee to serve as director of national intelligence, John Ratcliffe, withdrew his name from consideration for the job in August of 2019 amid tepid support from Republicans and charges that he had exaggerated his national security credentials.

When Trump nominated Ratcliffe a second time for the nation’s top intelligence job, Republican lawmakers such as Graham, then-Senate Intelligence Committee Chairman Richard Burr (R-N.C.) and Sen. Marco Rubio (R-Fla.) expressed stronger support for him, leaving observers baffled as to what had changed.

“I’m anxious to talk to my Republican colleagues who expressed serious concerns about him prior. I don’t know what in his background or his résumé puffing has gone away,” said Sen. Mark Warner (D-Va.), vice chairman of the Intelligence Committee, who has had a good working relationship with Republicans on his panel.

The Senate voted to confirm Ratcliffe May 21 on a party-line vote.

Despite many signs that Trump is strengthening his grip on the party, there’s evidence that a sizable minority of Republicans continue to have doubts about his leadership style.

An analysis of polling by FiveThirtyEight, a website that tracks and analyzes data, found that on average 82 percent of Republicans approve of the president’s handling of the coronavirus pandemic.

The data is more worrisome for Republican lawmakers in swing states, as polling averages show that only 38.5 percent of independents approve of Trump’s response to COVID-19.

Yet Trump has received little to no criticism from Republicans in Congress as he has moved to oust watchdogs within his administration who have pointed out or threatened to point out mistakes.

The president has moved to remove four inspectors general within the last several months, including Christi Grimm, the inspector general of Department of Health and Human Services, after her office published a report on hospitals around the nation facing a critical supply of testing and personal protective equipment during the pandemic.

Sen. Mitt Romney (Utah), one of the president’s few outspoken Republican critics in Congress, said Trump’s personnel moves had “the potential of sending a chilling message.”

After Trump announced his decision to fire State Department Inspector General Steve Linick on May 15, a Friday, Senate Republicans said they wanted a detailed explanation from the president of his reasons.

But when Trump met with GOP senators for lunch a few days later on May 19, he dominated much of the discussion, and the subject of Linick’s firing didn’t come up. 

Trump urged Senate Republicans at the time to “get tough” with Democrats and stay unified over the summer and into the fall campaign season.