David Jackson

USA TODAY

DALLAS — A nationwide fundraising tour doesn't seem to be improving the relationship between Donald Trump and members of the Republican Party leadership.

As Trump travels cross-country to raise campaign money in conjunction with the Republican National Committee, a rising number of GOP lawmakers say they will not endorse the presumptive presidential nominee and may not even vote for him come November.

"We're like two companies," said Ohio Gov. John Kasich, speaking to MSNBC about a recent phone conversation with Trump. "We have different values, different visions — kind of hard to put that together."

Kasich, one of Trump's defeated rivals in the Republican primaries, added: "I'm a uniter, and it's hard for me to go for somebody who's a divider."

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In recent days, Republicans like Maryland Gov. Larry Hogan and Rep. Fred Upton of Michigan have also refused to endorse the party's presidential candidate, and it appears that this kind of reluctance is starting to annoy Trump and his backers.

"You know the Republicans — honestly folks, our leaders have to get tougher,” Trump said during a rally this week in Atlanta, part of a tour that has included stops in New Hampshire, North Carolina and Texas. “This is too tough to do it alone, but you know what I think? I’m going to be forced to.”

Trump fans who gathered Friday night at a hotel/convention center complex in The Woodlands, near Houston, said most of the Republicans opposing their candidate are members of "the establishment" who fear losing power.

"They don't want to be exposed, so they've got to stick together," said Connie Reyes, 65, a realtor from Spring, Texas, who backed U.S. Sen. Ted Cruz during the primaries. "The Republicans are more united than people think."

Raven Clepper, 28, a certified nursing assistant from Humble, said the party "needs to be united for the greater cause" of beating Clinton. Some Republicans may continue to oppose Trump for "their own agendas," but most will wind up with him as Election Day nears. "The closer it gets, they'll get on board," she said.

During a Thursday rally in Dallas, Trump backer Andy Nguyen inspired boos from a supportive crowd when he mentioned Republicans who are talking about "not voting at all" in the general election contest with Democrat Hillary Clinton.

"The time for debate and argument among ourselves is past," said Nguyen, a commissioner in neighboring Tarrant County. "We have a nominee for president and there is no more time to waste."

Rep. Michael Burgess, R-Texas, who backed Ted Cruz in the primaries and is now pro-Trump, told the Dallas crowd that some Republicans are endorsing the New York businessman only because he is the one on the ballot.

"I didn't say I was endorsing 'the nominee of the party,'" Burgess said. "I endorsed the man, Donald Trump. I endorsed what he stands for."

Some Republican officials said the party is coming together behind Trump as the nominating convention approaches July 18-21 in Cleveland.

Reince Priebus, chairman of the Republican National Committee, flew to Dallas with Trump and disputed the notion of friction between the party and its nominee.

"Reports of discord are pure fiction," Priebus tweeted. "Great events lined up all over Texas. Rs will win in Nov!"

On Friday, Trump had a fundraising event in San Antonio as well as the rally near Houston. The nominee-in-waiting wraps up his weeklong tour Saturday in Las Vegas and Phoenix.

House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell have endorsed Trump, however tepidly, but have criticized him in recent weeks, notably his attacks on the federal judge hearing a fraud case against Trump University, who Trump said be biased by his "Mexican heritage." Other Republicans hit Trump this week for comments about the behavior of U.S. soldiers in Iraq, though aides said the candidate was referring to Iraqi soldiers.

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Trump is actively opposed by his direct predecessor, 2012 Republican nominee Mitt Romney. (For his part, Trump says Romney is jealous, having "choked" away a winnable race against President Obama four years ago.)

The party's last president, George W. Bush, has announced plans to raise money for embattled Republican senators — but his office has said he will not attend the GOP convention, nor will he participate in or comment on the presidential race.

There is even some talk of trying to "dump Trump" at next month's convention, though that possibility appears remote, given the number of pro-Trump delegates who will be in attendance.

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Bill Kristol, longtime foe of Trump and editor of The Weekly Standard, is urging the party to "cut the thread" with the still-presumptive nominee.

In his magazine's new issue, Kristol writes that "Trump's ghastly performance over the last couple of weeks has revived the question of an open convention, where delegates would have it in their power, should they choose to exercise it, to nominate any eligible citizen for consideration by the convention and to vote their conscience in a secret ballot."

There is some question as to how much influence Republican politicians have with rank-and-file voters.

While new polls in recent days show Clinton is building a lead on Trump — with the help of independent voters — Trump still has strong numbers among Republicans.

Poll: Clinton 12 points ahead of Trump nationally

GOP pollster Frank Luntz said, "Trump didn't win because of endorsements, and he won't lose because of them, either," because the views of politicians don't matter to his voters.

"In fact, it's a badge of honor to them," Luntz said.

Republican voters alone won't be enough to win a general election, however.

Matt Mackowiak, a Republican political consultant in Austin who hasn't decided whether to vote for Trump, said he senses real concern within the party that the presumptive nominee will hurt GOP candidates for the Senate and House, possibly costing them control of Congress.

"I think panic is starting to set in," he said.