CASTLE ROCK, Colo. (AP) - Republican vice presidential candidate Paul Ryan told supporters Sunday that running mate Mitt Romney "will become a great president."

Ryan made the comments in a county fairground's barn in Colorado, the fourth of five states he visited Sunday.

He said supporters shouldn't be in a position to regret not working harder to elect Romney as president Tuesday. He said no one wants to wake up Wednesday asking if they did everything they could.

Ryan said he understands why voters loved President Barack Obama's message of "hope and change," but he encouraged the crowd to talk to their unhappy neighbors and urge them to vote for Romney.

Earlier Sunday, during an event in Minneapolis, Ryan promised: "Mitt Romney and I are not going to duck the tough issues. We're not going to kick the can down the road.

"We are not going to spend the next four years blaming other people, Ryan said. "We're going to take responsibility."

Ryan also campaigned in Wisconsin and Ohio on Sunday. After Colorado, he flew to Nevada for an early Monday event in Reno.