U.S. Sen. Joe Donnelly (D-Ind.) is hopeful he will have a chance to confirm a Supreme Court justice to replace the late Antonin Scalia this year, but he isn’t holding his breath either.

Senate Majority Leader Mitch McConnell (R-Ky.) announced Sunday that he would block any nominee until a new president takes office in January 2016. Presidential candidate U.S. Sen. Ted Cruz (R-Texas) promised to filibuster any nominee President Barack Obama named.

Donnelly calls such action a “dereliction of duty.”

“Part of the Constitution requires (Senators) to take nominations the president gives us and work on them,” he said during an interview Monday morning. “If they meet all qualifications, (we) confirm them. If not, (we) send it back and ask the president for another.”

He predicts Obama will have a nominee within a month. Donnelly prefers a moderate candidate who is more concerned about doing what’s right for the country rather than subscribing to an extreme on either side.

As for whoever takes the Oval Office in 2016, be it a Democrat or a Republican, Donnelly said they shouldn’t be concerned with who replaces Scalia.

“When the next president is in office, when they have Supreme Court vacancies, they can fill those,” he said.