Obama gains momentum against Romney, all eyes on Ohio WASHINGTON (Reuters) - President Barack Obama rolled up victories in Wisconsin and Pennsylvania on Tuesday and limited Republican challenger Mitt Romney's path to victory as U.S. voters decided between two starkly different visions for the country. Obama's victories in the two states put pressure on Romney to score victories in Ohio, Florida and Virginia, three battleground states where the race was too close to call. At least 120 million people were expected to decide between the Democratic incumbent and Romney after a long, expensive and bitter presidential campaign centered around how to repair the ailing U.S. economy. In the state-by-state battle to get to 270 electoral votes needed for the presidency, Obama and Romney piled up early victories in the states they were expected to win easily. Early vote-counting in the swing state of Florida showed them running neck-and-neck. Obama led in the critical battleground state of Ohio and Romney held an early lead in a third swing state, Virginia. Romney needs all three of those states to navigate a narrow path to the presidency, while Obama could afford to lose one or two of them and still win a second four-year term. The Republican's chances were hit by Obama victories in Wisconsin and Pennsylvania, as well as New Hampshire. Romney last week visited Wisconsin, home state of his vice presidential running mate, Paul Ryan, and had stopped in Pennsylvania earlier on Tuesday in hopes of pulling off a surprise win there. In a victory that also limited Romney's path to a victory, Obama won Michigan, the Republican's state of birth but where he ran afoul of voters by opposing an auto industry bailout pushed by Obama. Some polls had shown a tight race there. Television networks projected Romney the winner, as expected, in Republican states Alabama, Tennessee, Mississippi, Kentucky, West Virginia, Oklahoma, South Carolina and Indiana. He was declared the winner in Texas, Kansas, Louisiana, Nebraska, North Dakota and South Dakota. Obama was projected the winner in the Democratic strongholds of New York, New Jersey, Maryland, Vermont, Connecticut, Delaware, Massachusetts and his home state of Illinois, as well as Washington, D.C. Who Americans choose will set the country's course for the next four years on spending, taxes, healthcare, the role of government and foreign policy challenges such as the rise of China and Iran's nuclear ambitions. Each man offered different policies to cure what ails America's weak economy, with Obama pledging to raise taxes on the wealthy and Romney offering across-the-board tax cuts as a way to ignite strong economic growth. National opinion polls before the election showed Obama and Romney in a virtual dead heat, although Obama had a slight advantage in several vital swing states - most notably Ohio - that could give him the 270 electoral votes needed to win the state-by-state contest. Three-quarters of both Romney and Obama supporters decided to vote for their preferred candidate before the October debates between the candidates, according to the data. Romney made last-minute visits to Ohio and Pennsylvania on Tuesday to try to drive up turnout in those states, while Vice President Joe Biden was dispatched to Ohio. Obama's Democrats are now expected to narrowly hold their Senate majority, while Romney's Republicans were projected to retain House control. Former Maine Governor Angus King won a three-way contest for the Senate seat of retiring Republican Olympia Snowe. King ran as an independent, but he is expected to caucus with Democrats in what would amount to a Democratic pick-up. Florida Democratic Senator Bill Nelson easily beat back a challenge from Republican congressman Connie Mack to win a third term, while Democratic congressman Chris Murphy beat Republican Linda McMahon, a businesswoman who had served as chief executive of a professional wrestling company. Democrat Elizabeth Warren won the U.S. Senate seat for Massachusetts. In the high-profile Senate race, Warren, a law professor who headed the watchdog panel that oversaw the government's financial sector bailout, defeated incumbent Republican Senator Scott Brown. Additional reporting by Jeff Mason in Chicago, Patricia Zengerle in Boston, Edith Honan in New York, Brendan O'Brien in Milwaukee, Dave Warner in Philadelphia, Philip Barbara in New Jersey, Matt Spetalnick, Lisa Lambert, Susan Heavey, Thomas Ferraro, Susan Cornwell, Anna Yukhananov and Roberta Rampton in Washington; Writing by Steve Holland and John Whitesides; Editing by Claudia Parsons and Will Dunham