WASHINGTON -- The bruising U.S. presidential election campaign is down to the wire, with Barack Obama and Mitt Romney now in the home stretch of one of the tightest races in contemporary American history.

A mere four days until Tuesday's vote, election day was looming with the candidates in a statistical tie. New jobless numbers released Friday provided neither politician the opportunity to break free of the dead heat -- though not for lack of trying.

The Obama campaign trumpeted the fact that the U.S. economy created 171,000 jobs in October, the second straight month of a jobless rate below eight per cent, allowing the president to assert that his economic policies are working.

Team Romney, meantime, maligned the president for a tiny uptick in the unemployment rate, from 7.8 per cent in September to 7.9 per cent in October. The economy is at a "virtual standstill," Romney charged on the campaign trail.

Nonetheless, a flurry of new polls in critical battleground states continued to show Obama with the narrowest of leads over his rival for the White House. He's edging Romney in Ohio, Florida and Virginia, while the Republican leads Obama in Colorado by a single percentage point, according to a Reuters/Ipsos survey.

Were he to hold on to those leads, Obama would become the first incumbent president since Franklin D. Roosevelt to win a second term when unemployment was above 7.4 per cent.

A loss would put him alongside Gerald Ford, Jimmy Carter and George H. W. Bush as incumbents who were forced out of the White House when the jobless rate was above seven per cent.

With their eyes on the finish line, Obama and Romney continued their blitz of swing-state campaigning on Friday, on the hunt for the 270 electoral college votes that will win them the election. Their politicking follows a brief hiatus brought on by mega-storm Sandy.

"America has always done best when everybody has a fair shot, and everybody is doing their fair share and everybody is playing by the same rules," Obama told a raucous crowd in Ohio on Friday.

"That's what we believe. That's why you elected me in 2008. And that's why I'm running for a second term as president of the United States of America."

Romney, meanwhile, promised to be the bipartisan leader Obama failed to become after being propelled to the White House in 2008 on a message of hope and change.

"I will reach out to both sides of the aisle," Romney said in Wisconsin.

"I will bring people together, doing big things for the common good. I won't just represent one party, I'll represent one nation. I'll try to show the best of America, at a time when only our best will do."

The campaigns' weekend travel plans made plain where Tuesday's election will be decided.

Obama will be in Ohio on Saturday, Sunday and Monday. He also scheduled to jet in for various appearances in Wisconsin, Iowa, Virginia, Florida, New Hampshire and Colorado. Romney will be in Ohio, Iowa, Wisconsin, New Hampshire, Colorado and Pennsylvania.

The candidates are making their final arguments at campaign rallies and in a slew of television ads --at least some of which are the subject of controversy.

In Ohio on Friday, Obama assailed Romney for a series of new ads that stoke false fears about Jeep moving production and jobs from the U.S. to China. Some of the country's auto executives have chastised Romney for the misleading ads.

"Everyone knows it's not true. The car companies themselves have told Gov. Romney to knock it off," Obama said, accusing Romney of attempting to frighten the state's autoworkers into voting for him.

"You don't scare hard-working Americans just to scare up some votes. That's not what being president is all about. That's not leadership."

A new Obama ad, meantime, features praise from a former Republican secretary of state, Colin Powell, who lauded the president's record and urged Americans to "keep on the track that we are on."

The president also received an unexpected endorsement from New York Mayor Michael Bloomberg, once a Republican and now an independent.

The mayor cited Obama's steady hand this week overseeing the federal response to Sandy, adding he wanted someone in the White House who would address climate change in the aftermath of the ferocious storm. Climate change, indeed, would reportedly be a top Obama priority in a second term.

The spectre of 2000's recount was also fresh in the minds of both campaigns in the midst of the horse race.

Twelve years ago, a clear victor didn't emerge until more than a month after election day when the U.S. Supreme Court effectively handed the presidency to George W. Bush by putting the brakes on a Florida recount.

With those memories top of mind, thousands of lawyers from both presidential campaigns will be at polling stations in key battleground states on Tuesday to keep an eye on their opponents and launch legal action if necessary.

Among other things, they'll be looking out for voter intimidation, how voters are instructed and how poll workers conduct themselves.

Democrats say they fear polling station shenanigans in swing states, including Republican-friendly poll workers sending voters to the wrong precincts.

"In each battleground state, we are recruiting thousands of attorney volunteers to help recruit, train, educate and observe at polling locations," the Obama campaign said in a statement.

"We've retained or opened pipelines to the nation's top experts on voting systems, registration databases, ballot design, student voting, and provisional ballots."

Tuesday's vote could also represent a rarity in American politics: the victor could lose the popular vote while winning the election.

That's because under the American system, the candidates compete not for popular vote, but for the 270 electoral college votes up for grabs stateside. Those votes are assigned based on a state's population and representation in Congress.

California, a reliably Democratic state, has the most electoral college votes of any state in the union, with 55.