MADISON, Wis. (AP) — A Republican senator suggested on Thursday that the Senate might consider filling the current vacancy on the U.S. Supreme Court if President Barack Obama were a conservative.

Wisconsin Sen. Ron Johnson, who faces a tough re-election contest in November, has been united with other Senate Republicans in opposing moving forward with any Obama nominee to replace Antonin Scalia, who died last month. But on Thursday, Johnson suggested things would be different if Republican Mitt Romney were president.

"It's a different situation," Johnson said in response to the hypothetical question from the "Morning Mess" radio host. "Generally, and this is the way it works out politically, if you're replacing — if a conservative president's replacing a conservative justice, there's a little more accommodation to it."

Johnson faces Democrat Russ Feingold this November in a rematch of their 2008 race. Feingold has joined with other Democrats in saying the Senate should move ahead with consideration of whoever Obama may nominate.

Johnson has branded Feingold a hypocrite because when he was in the Senate in 2006 he supported a filibuster of President George W. Bush's nomination of current Justice Samuel Alito. Feingold has said that's different because he didn't oppose Bush's ability to put forward a nominee, he just objected to Alito being the one.

Johnson reiterated his position in the Thursday interview that he's worried an Obama nominee would flip control of the court from conservatives to liberals. He said waiting to confirm the next Supreme Court justice next year after the election would be "very reasonable" and "probably the fairest thing to do."