That may explain why, though Lopez said Trump’s comments didn’t offend him, he was quick to distance himself from the real-estate mogul.

“With my network and reputation here in Colorado, and people understanding what I stand for, I know they’re not going to connect me to Trump,” he said. “My network will be able to clearly articulate what I represent — which is not close to what Donald Trump represents.”

That’s because what Donald Trump has come to represent over the past few weeks is not just his typical bombast and bluster but what some critics have decried as blatant racism. And there’s growing concern among Republicans that Trump’s outsized profile could cause real damage, not only to the GOP’s 2016 hopes, but to the party’s chances of defending a fragile majority in the Senate as well.

“There’s a lot of concern that Trump’s very overheated and unsolicitous rhetoric is really a gift for Democrats,” said one Republican strategist advising a Senate candidate in a key battleground state, who was granted anonymity to speak frankly on the issue. “And it obscures, as Marco Rubio says, a lot of the real problems surrounding the immigration debate.”