OSHKOSH, Wis. - Vice President Joe Biden visited northeast Wisconsin early Friday in a bid to shore up support in a region that's a must-win if President Obama is to carry the Badger State and its 10 electoral votes.

"We need you," Biden told a cheering rally of about 1,000 at the University of Wisconsin-Oshkosh. "Together, we can win Wisconsin. If we win Wisconsin, we win this election."

Biden's visit, his fifth to Wisconsin this year, came amid tightening polls that show the state could be within the grasp of Republican Mitt Romney. Obama won the state almost four years ago with a 14-point margin, but recent surveys indicate his lead has narrowed to single digits.

Biden used his visit on Friday to slam Romney and his running mate, Wisconsin Rep. Paul Ryan, for a foreign policy "right out of the Cold War," their positions on women's rights and what the vice president said was a last-ditch effort by the Republicans to flee from their records.

"He was attempting to rewrite recent history," Biden said of Romney's performances in the presidential debates. "I didn't know that he was there to endorse Barack."

And deploying a favored term of the Obama campaign - "Romnesia" - Biden mocked Ryan in his home state.

"It is contagious," Biden said. "Poor Paul caught it."

Wisconsin has voted for the Democratic presidential nominee in seven of the last 10 elections, but Republican George W. Bush nearly picked off the state in both 2000 and 2004.

The Romney and Obama camps are both scrambling in the election's final days to make their closing arguments to Wisconsin voters.

Obama is scheduled to travel to Green Bay on Tuesday to rally his backers in Brown County, which swung from voting Republican in 2004 to supporting Obama in 2008. Obama's trip will be his second to Wisconsin in October.

Meanwhile, Romney is scheduled to arrive Monday night in Milwaukee in his first visit to Wisconsin since August.

Top Democrats acknowledge the stakes here and the little room for error.

"What happens in Wisconsin may determine who is the next president," retiring Sen. Herb Kohl, D-Wis., said. "Who knows that 5- or 10- or 15,000 votes won't determine the way Wisconsin votes?"

Republicans are similarly invigorated, and analysts say a failed attempt to recall Gov. Scott Walker has energized the GOP's base and helped strengthen the party's statewide organization.

"It helped the Republican Party's organization and get-out-the-vote effort a great deal," said Michael Wagner, a University of Wisconsin political scientist. "The Republicans in Wisconsin are a little more prepared to handle the Obama campaign's very aggressive voter turnout strategy than Republicans in other states."