Sen. Lindsey Graham is worried Donald Trump's floundering presidential campaign will cost the Senate Republicans their majority.

"People are getting pretty nervous about our candidates because he's in a death spiral here and nobody knows where the bottom is at," the South Carolina Republican told the New York Times.

The Republican presidential nominee overhauled his campaign this week following a string of controversial comments that angered many in the party. But it is unclear if that will help Trump avoid the fall he's seen in recent national and state polls.

Specifically, Republicans worry that Trump's struggles in the swing states of Pennsylvania, New Hampshire and North Carolina — where Democratic nominee Hillary Clinton has clear advantages in many polls — will determine the control of the Senate in November.

Senate Republicans up for re-election are stuck in the tricky position of either supporting their party's candidate or trying to distance themselves from him based on their constituents.

"It's going to be like 'Weekend at Bernie's' — you got to make him look alive, even if he's not," said Graham, who is not supporting Trump.

This week, Graham, who had a failed presidential campaign of his own, predicted Trump has alienated voters so strongly that he will be decimated in the general election in November.

"Mitt Romney got 27 percent of the Hispanic vote. By 2050, a majority of the country will be African-American, Hispanic, Asian and others, and we're losing demographically. We've gone from 44 percent with Bush to 27 percent with Romney, and I don't think Donald Trump's gonna get 20 percent," Graham said.

According to a RealClearPolitics average of national polls, Trump trails Clinton by 6 percentage points.