Sen. Joe Manchin on Sunday said he believes “in my heart of hearts” that President Trump would sign a bill to expand gun background checks that he’s co-sponsoring with a Republican colleague, but warned that a proposal to place limits on semiautomatic weapons could doom his measure.

“I really believe he would,” the West Virginia Democrat said on CNN’s “State of the Union. “In my heart of hearts I believe that.”

Asked what effect Democratic Sen. Dianne Feinstein’s proposal to ban some semiautomatic weapons would have on his bill, Manchin said it would be fatal.

“It would not help our bill at all,” Manchin said. “And I told Dianne that.”

The measure he is cosponsoring with GOP Sen. Pat Toomey’s would expand federal background checks to cover sales online and at gun shows.

Trump appeared to signal support for the measure when he hosted a White House meeting last week attended by Manchin and Toomey of Pennsylvania.

But White House Press Secretary Sarah Huckabee Sanders backed off that stand last Friday, saying that while Trump wants to “focus and improve” the background check system, he wasn’t yet fully on board with universal checks in the Manchin-Toomey bill.

“Universal means something different to a lot of people,” she said.

Manchin, who is running for re-election in a state Trump won by 40 percentage points in 2016, was quick to point out that he fully supports gun ownership.

“I’m not taking anybody’s guns away from them,” Manchin said. “There’s not a law-abiding gun owner in America that doesn’t believe that if you go to a gun show and if you go on the internet, you need to know through a commercial transaction who the person is and what their intent – and what their background [is]. That’s all. We protected all the rights of law-abiding gun owners.”

They revived the bill they first introduced after the Sandy Hook Elementary Schools shootings in December 2012 but the Senate shot down in 2013.

Manchin expressed frustration that the Senate could refuse to act again even with renewed calls for gun control and school safety proposals after the shooting of 17 people at a Florida high school on Feb. 14.

“It’s a high probability that could happen if this thing goes mute,” he said.