(The Hill) — Republican lawmakers say the Trump campaign was caught off guard by President Joe Biden’s decision to drop his reelection bid and that the former president’s team has faltered in responding to the surge of momentum behind Vice President Kamala Harris.

Some Republican senators think former President Donald Trump should have seen the swap atop the Democrat ticket coming and crafted a messaging and political strategy weeks ago.

They see Trump’s awkward discussion about Harris’ racial heritage at the National Association of Black Journalists convention as a clear sign the Trump campaign hasn’t yet hammered out a workable strategy for Harris.

GOP lawmakers also view Trump’s selection of Sen. JD Vance, R-Ohio, as his running mate as evidence that Trump didn’t expect Biden to drop out of the race. They worry Vance’s outspoken views on restricting abortion and his claim that “childless cat ladies” run the country play right into the message that Harris and Democrats will center their campaign on in the fall.

One Republican senator who spoke to Trump before he announced Vance as his running mate said the former president expressed skepticism that Biden would drop out of the race.

“I think they were caught off guard. I think they were surprised,” the senator said. “I think there was shock when the Democrats revived [their party] really quickly” and unified support behind Harris.

“I think she’s more formidable than Republicans give her credit for. It’s going to be a short election, that favors her. It’s going to be sprint. We’re used to these long elections. This one’s going to end up being short. That helps her,” the lawmaker said of Harris, who announced she had raised $310 million for her campaign in July.

The lawmaker said Trump’s selection of Vance as his running mate to combat Biden’s strength in Michigan and Pennsylvania, specifically, showed he expected Biden to be his opponent in the fall.

A second GOP senator in contact with Trump who requested anonymity to speak candidly about the campaign said the GOP nominee and his team weren’t ready for the entire Democratic Party to rally behind Harris within a few days of Biden dropping his reelection bid.

“I think it was a surprise,” said the lawmaker. “I wasn’t surprised at all. I was already betting on a different nominee. What was impressive to me was how quickly they consolidated” behind Harris.

Sen. Lindsey Graham, R-S.C., one of Trump’s closest allies in the Senate, insisted in an interview with The Hill that Trump thought Harris taking over the Democratic ticket was a possibility.

But Graham acknowledged that Trump is having difficulty finding a message that hits home against Harris amid widespread Democratic enthusiasm about her campaign.

“It’s pretty hard, she’s sort of having a honeymoon period here. I think the way forward is she empowered the decision to withdraw from Afghanistan, she was the border czar, on and on and on. Her policy choices have been disastrous for our country. I think that’s the theme,” he said.

Democrats say Republicans have mischaracterized the Harris record by calling her the “border czar,” pointing out that she was authorized to take the lead on addressing the root causes of migration from the Northern Triangle countries of Guatemala, El Salvador and Honduras, and not put in charge of border security, per se.

Senate Republican strategists found themselves scrambling on the Sunday afternoon Biden dropped out of the race and the following Monday to dig up details on Harris’s record in the absence of a well-coordinated response led by Trump’s campaign.

Trump repeatedly made false claims about Harris’s record during his first campaign rally Thursday since she became the presumptive Democratic nominee and appeared far less familiar with her record than with Biden’s.

He accused Harris, falsely, of wanting to lift the Social Security retirement age, of heading up the criminal and civil prosecutions against him and of wanting to outlaw red meat to fight climate change.

On Wednesday, Trump dropped one of the biggest bombshells of the campaign by falsely claiming that Harris had embraced her Black identity only a few years ago and insisted he didn’t even know if she was Black or Indian.

The comments set off an uproar on Capitol Hill. Democrats condemned Trump’s mocking of Harris’s racial identity while Republicans rushed to distance themselves from their nominee’s remarks.

GOP senators said Trump’s response to Harris’s entry into the race show the hallmarks of someone who was unprepared for a dramatic turn in the race, even though Biden had been under intense pressure since his disastrous June 27 debate to step aside.  

Trump on Thursday again tried to make an issue of Harris’s race by circulating a photo of Harris dressed in a sari, a traditional Indian garment, alongside her mother, who was born in Chennai, India.

“Thank you Kamala for the nice picture you sent from many years ago! Your warmth, friendship, and love of your Indian Heritage are very much appreciated,” Trump wrote in an ironic caption.

His post flew in the face of advice from allied GOP senators who were urging him Thursday to drop the talk about race and focus on policy differences, instead.  

“If you’re running for president or if you want to be CEO of a company, a campaign built on insults of an individual — we should be so far beyond that. It should not be about which nasty name you call somebody,” Sen. Lisa Murkowski (R-Alaska) said Thursday.

“It should be about the issues. I think the American people deserve more than what we’re seeing with this approach to a campaign. I just think it’s wrong,” she said.

A third Republican senator said Trump was “not prepared” for Biden to drop out and for Democrats to agree upon Harris as their nominee so quickly.

The lawmaker said Trump seems to have assumed that the political arguments he had been crafting against Biden for years could be shifted over effectively to his vice president, but Harris’s political brand has so far shown itself to be resilient from the old attacks used against the president.

“I think they were counting that if it did happen, the negativity that she experienced in the three-and-half years would immediately take over, and that has not happened,” the senator said.

A fourth Republican senator who is a strong Trump ally said, “I do think they were caught a little off guard,” referring to Trump and his inner circle of advisers.

“I kept hearing from my Democrat colleagues that there’s no way President Biden won’t be in the race because he’s the only person that ever beat Trump, and they would stick with him through think and through thin. And then that didn’t happen,” the lawmaker said. “All the conventional wisdom, even coming from Democrats, was Biden was going to go the distance.”