Donald Trump’s performance the past month — the countless controversies and continual taunts of the GOP establishment — is dramatically narrowing his options for vice president.

With the Republican convention a month away and Trump approaching a critical decision on his No. 2, each week crosses more names off the list. Trump has bashed star Republican Gov. Susana Martinez of New Mexico and ignored the advice of senators like Bob Corker of Tennessee, who might have brought valuable foreign policy and congressional experience to the ticket. Florida Sen. Marco Rubio has ruled out the post (even as he reconsiders running for reelection), while South Carolina Gov. Nikki Haley and Iowa Sen. Joni Ernst — both well-regarded GOP figures who might improve Trump’s dismal standing among women and minorities — have all but done the same.


And Gov. John Kasich, who might have helped Trump in must-win Ohio and heal wounds with the party establishment, can’t even bring himself to support the presumptive nominee.

“It’s not going to make it easier” to select a running mate, Sen. John Thune of South Dakota said of Trump’s recent behavior. The Senate’s No. 3 Republican, Thune himself has been mentioned as a potential running mate. “There are probably some good options for him. The question is: Are there people for whom he is a good option?”

John Weaver, who served as the campaign strategist for Kasich’s presidential bid, was more blunt: “I can't imagine a truly credible person agreeing to be his running mate, because it would be the end of his or her political career.”

Ironically, the presumptive nominee’s own toxicity is making the job of finding a vice presidential nominee that much easier, because the short list is so short. Multiple high-level Republican sources said it is topped by New Jersey Gov. Chris Christie and former House Speaker Newt Gingrich, with Alabama Sen. Jeff Sessions a distant third and Oklahoma Gov. Mary Fallin also in the mix.

Christie and Gingrich are both skilled communicators who could perform credibly on the convention stage and in a head-to-head debate with their Democratic counterpart in the fall. Both also bring the political experience Trump lacks. But there’s another, simpler reason why these two white men, both more representative of the Republican Party’s past than its future, have emerged as finalists: They actually want the job.

Trump's campaign declined to comment. But during the primary campaign, he said that he wants a vice president who knows the Capitol and can help him pass an agenda.

"I want to have somebody who can deal with Congress, who gets along with Congress, who is a Washington person," he said at a town hall in April.

But if he changes his mind and looks beyond the Beltway, Christie and Fallin are believed to be high on his list.

Fallin was among a handful of supportive red-state governors to meet with Trump in New York this week. She's expressed a willingness to join the ticket and could help the presumptive nominee with women, three-quarters of whom disapprove of him, according to an ABC News poll.

Trump has also courted a number of Southern governors, including Nathan Deal of Georgia, Asa Hutchinson of Arkansas, Bill Haslam of Tennessee and Phil Bryant of Mississippi. Should any of them be added to the ticket, though, they would do little to broaden Trump’s appeal beyond his base. None has been tested on the national stage.

More centrist GOP governors, like Michigan’s Rick Snyder, whose state the campaign views as a critical piece of its electoral math puzzle, and Maryland’s Larry Hogan, have refused to even endorse Trump.

Sessions, the first senator to endorse Trump and one of his strongest defenders, said he’s ready if the phone rings.

“I’d consider it, certainly. I don't know if I could help him. He needs someone that would be an asset to the ticket who could be a great president,” Sessions said. “There are a lot of people better than I out there.”

That may be true on paper, but the options are dwindling.

Christie, one of the first establishment Republicans to endorse Trump, is in his second term as New Jersey governor and just saw his approval rating fall to a record-low 26 percent last month. Gingrich, a presidential candidate himself in 2012, is a political pundit who, at 72, is unlikely to ever run for office again on his own. And 69-year-old Sessions is often critical of the congressional GOP’s priorities and would do little to soothe his colleagues worried about a President Trump.

Tim Scott has also drawn some buzz as a potential pick. The first-term South Carolina senator is well respected in the chamber and would bring diversity to Trump's ticket as the sole African-American GOP senator. Scott is backing Trump, even as he called the candidate's criticism of a judge with Mexican roots "racially toxic."

In an interview, Scott said his political staff has spoken to Trump’s campaign but that it has been weeks since he’d spoken himself to Trump. He acknowledged he’s “open to a conversation” about serving with Trump, but would go no further.

Beyond the question of his vice president, there’s growing demand for Trump to reassure Republicans about his Cabinet, as he did last month by releasing a list of potential Supreme Court nominees.

With frequent questions about how Trump would handle relationships with U.S. allies and the country’s foreign policy overall, some Republicans are clamoring for names of potential secretaries of defense and state, too.

“Trump would be well served to identify a list of senior statesmen that he might appoint to those positions,” said one Republican senator who’s pledged to support the nominee.

Plus, it would give the media and the GOP something to talk about besides the latest Trump controversy.

“That could divert some of the attention he’s getting now. So that might not be a bad idea,” said Sen. Jim Inhofe (R-Okla.).

But the pool of candidates for those posts might be shrinking, too. Corker, chairman of the Senate Foreign Relations Committee, is practically despondent over Trump these days, after visiting with the presumptive nominee and expressing hope he could jolt Washington out of its perpetual state of gridlock.

Just weeks ago, Corker entertained the vice presidential speculation around him, saying he had no reason to believe he was being vetted but refusing to rule anything out. Now, he can’t bring himself to even discuss Trump.

“I don’t want to talk about any of that,” the senator said in an interview.

Sen. Lindsey Graham (R-S.C.), who has called Trump unfit for the presidency and refused to endorse him, said the presumptive nominee has himself to blame for the VP dilemma.

“As Trump’s numbers begin to stagnate or goes backwards, people will be thinking: ‘I don’t want to join this team.’ If he has a breakthrough moment, it goes the other way.”