WAUKESHA, Wis. - For John McCain, there were few bright spots four years ago in Wisconsin, which Barack Obama won by a double-digit margin.

But if there was a Badger State success story for McCain's lackluster campaign, it was in the Milwaukee suburbs, where a trio of counties gave him at least 61 percent of the vote in each locale.

With recent polls showing Mitt Romney within the margin of error in Wisconsin, analysts and activists on both sides say his chances to seize the state's 10 electoral votes may hinge on the GOP's ability to run up the score in historically -- and enthusiastically -- red communities like Waukesha County, just west of Milwaukee.

"It's a needed cog in the wheel," said Keith Best, a member of the county Republican Party's executive committee. "If we do what we're capable of doing and what we're fired up to do, we'll bring it home."

With the race here tightening, both parties are scrambling to protect turf they won four years ago and drive up vote totals. Romney is also seeking to recover parts of the state that McCain lost but have boosted GOP prospects in the past.

In 2008, only 13 of Wisconsin's 72 counties voted for the GOP ticket. That was a marked shift from 2004, when George W. Bush won 45 counties and came within 12,000 votes of defeating John Kerry in the state.

Both sides believe the contest will be far closer this time than in 2008, and after a bombardment of thousands of television advertisements, both campaigns are deploying their most valuable assets in the election's final sprint: the candidates themselves.

Democrats sent Vice President Biden to Oshkosh on Friday, and Obama will travel to Green Bay on Tuesday to rally support.

Romney, meanwhile, is set to make his first visit to Wisconsin since August on Monday night when he appears near Milwaukee. His running mate, Rep. Paul Ryan, will make stops throughout his home state later in the week.

The campaigns chose their spots carefully.

Northeast Wisconsin's Fox Valley, where both Green Bay and Oshkosh are located, is critical to Obama and Biden's hopes of notching another Wisconsin win. The region overwhelmingly voted for Bush in 2004.

But the region abruptly reversed itself in 2008. Brown County, which includes Green Bay, had a 10-point swing from red to blue, the largest in the state.

"It's a region every four years that we see being one of the top areas in the country where money is spent because there are so many swing voters there," said Milwaukee Mayor Tom Barrett, a Democrat who has run for statewide office in the past. "Clearly, both camps, I think, are focusing on that area because they know it's an area where voters really take an independent view, and it might change from election to election. It's not a place where you can take anything for granted."

Romney's choice for an event in Milwaukee's suburbs reflects an effort to generate voter enthusiasm in a deeply Republican region, which Sen. Ron Johnson, R-Wis., said could help offset Obama's strength in traditional Democratic strongholds.

"We have to try to minimize Obama's advantages in Dane County and Milwaukee County," Johnson said.

In 2008, Obama won 68 percent of the vote in Milwaukee County -- Wisconsin's most populous -- and 74 percent in Dane County, which includes Madison, the state capital.