Republican Sen. Josh Hawley of Missouri says he thinks former President Donald Trump will ultimately be the GOP nominee for president. But he hasn't taken the step of making a full endorsement in the primary campaign.

"No offense to anybody else who's running, but I just said I don't think the primary is a real contest. I think he's going to be the nominee, and I will absolutely support him against the current president," Hawley said. 

It's a consistent narrative on Capitol Hill. Many Republicans who supported Trump in his two previous presidential campaigns believe he has already clinched the GOP nomination for president, given his commanding lead in the polls, and they say there's no need for them to endorse him. 

So far, only 13 of the 49 Republican senators on Capitol Hill have officially announced their endorsement of Trump, including Sens. Tommy Tuberville of Alabama, Lindsey Graham of South Carolina and Rick Scott of Florida. 

"If he's the nominee, for certain — I just haven't made a decision yet on the primary at this point. I mean, it's not gonna make a difference one way or the other, but I haven't announced anything on that," Florida Sen. Marco Rubio said. Rubio faced off against Trump in 2016 for the GOP presidential nomination and dropped out after he lost the Florida Republican primary. 

Even some of Trump's most fervent supporters in the Senate aren't endorsing him yet. 

"I don't endorse in primaries. I don't endorse," Sen. Ron Johnson said while running into an elevator in the Senate basement. In 2022, Trump endorsed Johnson for a third term even before the Wisconsin senator had decided to run again.

Sen. John Kennedy of Louisiana, who was endorsed by Trump during his Senate reelection campaign in 2022, declined to say whether he would endorse Trump during the primary campaign. 

"I don't have anything for you on that," Sen. Kennedy said in response to a question from CBS News. 

Trump's highest-profile Republican Senate endorsement came from Montana Sen. Steve Daines, the head of the Senate's GOP fundraising arm, who said he would like to see more Republicans come out and endorse Trump. 

"He's going to be the nominee," Daines said. 

Sen. J.D. Vance of Ohio — one of the 13 Republicans who has been outspoken in his support of the former president — said he has been lobbying for more of his colleagues to endorse Trump, declaring the primaries are "effectively over'' before voting in the Iowa caucus has even begun. 

"Look, whether you like him or not, he's going to be the Republican standard bearer, and I think we have to get behind him," said Vance. 

No votes have been cast yet in the GOP presidential primaries. The Iowa caucuses, the first contest of the 2024 primary calendar, takes place on Jan. 15. Longtime Iowa Sen. Chuck Grassley says he won't be endorsing before the caucuses. 

"I do not plan on endorsing, and I believe that Joni Ernst has the same view I have. And the reason we haven't endorsed anybody is because when there were 13 candidates, we wanted everybody to come to Iowa and keep Iowa first in the nation," Sen. Grassley said. 

But Trump has criticized Grassley in recent weeks, arguing that he helped both Grassley and Ernst win their previous elections. During a "commit to caucus" event in Fort Dodge, Trump said, "I got a lot of guys elected right here, including Grassley, who was having a problem and including Joni Ernst, who had a big problem."

Grassley, who won reelection to his eighth term in the Senate in 2022, doubts Trump's endorsement was much of a factor. 

"I've had 36 elections. Long time before Trump ever knew who Chuck Grassley was, and I won every one of them," Grassley said. 

Other Republican senators are still shopping for a GOP presidential nominee and deciding whether to support Florida Gov. Ron DeSantis, former Ambassador to the U.N. Nikki Haley, entrepreneur Vivek Ramaswamy, former New Jersey Gov. Chris Christie or North Dakota Gov. Doug Burgum. 

Mitt Romney, the junior senator from Utah, said he hopes the GOP will have "a nominee other than former President Trump." 

"Nikki Haley is a very capable person. People didn't think she had much of a shot, but she's proved them wrong before, and she's doing it again," Romney said. 

Sen. Todd Young of Indiana says he thinks Haley has run a "great campaign" and believes she "certainly could win a general election." But Young stopped short of giving his full endorsement. 

Sen. Kevin Cramer of North Dakota said Burgum, his state's governor, still has his full support, but is leaving the door open after the primaries. 

"I'll let him get past these primaries and see what happens," Cramer said. 

When asked if he thinks Burgum, who is polling at about 1% among likely Republican primary voters, should stay in the race, Cramer responded, "I would never encourage him to do anything other than do whatever his pocketbook and his heart tells him." 

In:
• United States Senate
• Donald Trump
• Republican Party
• Chuck Grassley
• Nikki Haley