(NewsNation) — Sen. John Fetterman, D-Pa., says the commitment for Trump is “significant” in his swing state.

The election is “gonna be incredibly close here,” Fetterman said Thursday on “CUOMO.“

“You don’t have to understand why people are voting for him, but you have to acknowledge it’s real. … We have to fight for every last vote across states like Pennsylvania.”

According to Decision Desk HQ’s polling average, Vice President Kamala Harris has a slight lead in Pennsylvania.

U.S. Senator Bob Casey, a Democrat, and Republican challenger Dave McCormick met in Harrisburg for their first debate Thursday in Pennsylvania’s U.S. Senate race, as Democrats try to prevent Republicans from flipping the Senate red.

The candidates battled throughout the debate, often claiming the other was lying on the campaign trail and on the debate stage. 

Both candidates were largely unopposed in the spring primary, setting up a race that could swing the balance of power in the U.S. Senate.