Washington(CNN) Senate Majority Leader Mitch McConnell worries that Donald Trump could ruin the GOP's relationship with Hispanics beyond repair.
While he is committed to voting for Trump, McConnell, a Republican from Kentucky, said in an interview with CNN's Jake Tapper on Thursday that the GOP nominee could push Latinos away from the party in a way similar to how black voters distanced themselves from the Republican Party in 1964 when it was led by conservative Barry Goldwater.
Recalling how he supported Democratic president Lyndon Johnson over Goldwater that year, McConnell was asked if he worried Trump could have the same effect on Hispanics, who overwhelmingly view the real estate tycoon unfavorably.
"I do. I do," he said on "The Lead," pointing to Trump's recent scorching criticism of a prominent Republican Latina politician, New Mexico Gov. Susana Martinez.
"And I think the attacks that he's routinely engaged in, for example, going after Susana Martinez, the Republican governor of New Mexico, the chairman of the Republican Governors' Association, I think, was a big mistake," McConnell said.
Regarding Goldwater's vote against the 1964 Civil Rights Act, McConnell said, "It did define our party, for at least African-American voters, and it still does today. That was a complete shift that occurred that year and we've never be able to get them back. So I think it was a defining moment for Republicans with regard to the accomplishments that we had made for African-Americans going back to the Civil War."
McConnell has endorsed Trump and has been far less vocal about his problems with Trump's temperament or policy than House Speaker Paul Ryan, who formally endorsed Trump on Thursday after initially saying he wasn't ready to back his party's nominee, citing policy differences.
McConnell nevertheless signaled that he would not be a rubber stamp for Trump's agenda. Asked if he would draft legislation on Trump's behalf over a temporary ban of Muslims from entering the U.S., a signature Trump proposal, McConnell said: "I'd say no."
Asked if he was worried whether Trump would have a negative effect on down-ballot races, including Senate candidates, McConnell predicted that 2016 would be a "ticket-splitting election" where Americans choose different candidates for the Senate and the White House. And there's one Republican senator he's hoping in particular will return next year: Marco Rubio.
"I hope he will be drafted. Certainly everybody up here wants him to run," McConnell said of the 2016 presidential candidate, who is now retiring from the body but is facing pressure to stay. "He's a unique figure that ought not to be lost in the public arena."