Ohio Republican Sen. Rob Portman is facing a formidable challenge from Democrat Ted Strickland. | AP Photo Congress Vulnerable GOP senators duck and cover from Trump How's this for hair-splitting: They're supporting 'the nominee,' but not giving an endorsement to the New York billionaire.

At 11:30 a.m. on Wednesday, Sen. Rob Portman — facing a tough reelection battle against a popular former Democratic governor — strongly reaffirmed his support for John Kasich as the GOP presidential nominee.

Twenty minutes later, news broke that Kasich was out of the race.


Kasich's decision was just a formality, but it left businessman and reality TV star Donald Trump without any opponent and cemented his hold on the GOP presidential nomination.

For Portman and other Senate Republicans up for reelection in 2016, the clock has run out. There's no place left to hide on Trump. Like it or not, the next five months will mean a steady diet of Trump, Trump and more Trump.

With 24 GOP-held Senate seats up for grabs in November — including in swing states such as Ohio, Pennsylvania, and New Hampshire — Trump is a wild card that Republicans have tried to avoid dealing with for months. They're still ducking the question, but they can't avoid the reality for long. These GOP senators will head into the general election with Trump on the top ticket, and Democrats using every chance they can to tie them to him.

They will also face endless questions about Trump: What do they think of what he said today about women? Hispanics? Muslims? "The Wall?" Hillary Clinton now? Hillary Clinton in the past?

The barrage won't stop until Election Day.

Not one Senate Republican up for reelection this November has openly, unreservedly endorsed Trump, a stunning situation for a party's nominee. Only Sen. Jeff Sessions (R-Ala.) has formally backed him so far.

What Sen. Kelly Ayotte 's (R-N.H.) campaign said in a statement on Wednesday was typical of how her Republican colleagues are handling their standard bearer: She will "support the nominee," it said, without mentioning the word, "Trump."

“As she’s said from the beginning, Kelly plans to support the nominee,” said Ayotte campaign spokeswoman Liz Johnson on Wednesday. “As a candidate herself, she hasn’t and isn’t planning to endorse anyone this cycle."

So did Sen. Ron Johnson (R-Wis.), one of the most endangered Republicans this fall.

"As Ron has repeatedly said for months, he intends to support the Republican nominee, but he's focused on the concerns of Wisconsinites — not national political winds," said Brian Reisinger, spokesman for Johnson's reelection campaign. "That's why he’s making 20 stops all over the state this week and addressing the economic and national security concerns he's hearing in local communities."

Don Larson, an adviser to Sen. John Hoeven's (R-N.D.) reelection campaign, also stuck to the "support the nominee" phraseology.

"I can tell you that he is not endorsing in the presidential race and that he will support the nominee of the party," Larson said.

Larson added: "[Hoeven] is planning to go to the convention, but he is not a delegate." Which means Hoeven won't be involved in officially bestowing the nomination on Trump.

A source close to Sen. James Lankford (R-Okla.) said he wouldn't be endorsing Trump and didn't want to talk about him. But, the source added, if the choice in November were between Trump and Clinton, Lankford would back the Republican nominee.

An aide to Sen. Johnny Isakson (R-Ga.) noted that "Johnny has said all along that he’ll support the ticket."

Sen. Richard Burr (R-N.C.) was one of the few to mention Trump.

"I always said I would support the nominee, and it's clear @realDonaldTrump has won the #Republican Presidential Primary," Burr said on Twitter. "I look forward to working with Mr. Trump at the top of the ticket and to maintaining a #GOP Senate."

Burr, though, won't be attending the GOP convention. Neither will Ayotte, Johnson or GOP Sens. Lisa Murkowski of Alaska, John McCain of Arizona, Mark Kirk of Illinois, Jerry Moran of Kansas or Roy Blunt of Missouri.

A number of Senate Republicans on the ballot this year did not return calls or emails seeking comment on Trump or what his nomination will mean for their race or the party. With Congress on recess this week — possibly the best-timed recess ever for Republicans — it was easy to duck the question. At least for now.

Sen. Dean Heller — a vice chairman of the National Republican Senatorial Campaign Committee, whose main mission is to defend GOP incumbents — said he couldn't support Trump. But he won't back Clinton, either. Heller may instead vote for "none of the above," which is an option in his home state of Nevada.

"I vehemently oppose our nominee in some of the comments he made and issues he brought up during the campaign. Issues that he brought up [about] women and the Hispanic community across the West, I just can't agree with some of his positions," Heller told Nevada reporters on Wednesday. "But I will tell you that I will not be voting for Hillary Clinton. I have stated early on that I will not be supporting a candidate who is nothing more than a third term for the Obama administration."

Senate Democrats, for their part, were ecstatic about the chance to tie GOP incumbents to Trump, despite the fact that Hillary Clinton, their own all-but-certain nominee, is pretty unpopular herself.

"Republicans woke up this morning facing the fact that Donald Trump is the presumptive GOP presidential nominee, and that is a big problem for vulnerable GOP senators and Senate candidates," said a release from the Democratic Senatorial Campaign Committee. "It’s going to be even harder for them to explain their own out-of-touch records while running alongside Trump, the divisive and dangerous personality who has now taken over their party."

Portman may be in the most exposed position of any Republican incumbent during the next couple of months. The GOP's national convention is in mid-July in Cleveland, and the coronation of Trump as the Republican nominee will be hard for Ohio senator to ignore.

Portman also stands for everything that Trump has railed against: A consummate Washington insider and GOP establishment figure who used to be the U.S. trade representative.

"We’d like to welcome Sen. Portman to his election nightmare," said David Bergstein, a spokesman for Democrat Ted Strickland, the former Ohio governor who's challenging Portman. "With the Republican National Convention in Cleveland, there will be no rock that Portman can hide under to avoid his party's toxic nominee."

Portman, one of Kasich's most vocal supporters, told POLITICO last week that he's poised to outperform the Republican presidential nominee, meaning he wasn't prepared to let Trump's candidacy hurt him.

“I'm not Donald Trump and nobody perceives me as Donald Trump. I'm also not Ted Cruz. I'm not Hillary Clinton, I'm not a lot of people," Portman declared. "We just run our own campaign. ... We’ve been prepared to run ahead of the top of the ticket for the last year. That’s why we’re doing this unprecedented grass-roots effort and why we’re doing unprecedented outreach to groups that might not be traditional Republican voters and why we’re the most aggressive online than any campaign in the country as far as we can tell."

Burgess Everett contributed to this report.

