President Barack Obama and Republican challenger Mitt Romney make a frenetic dash to a series of crucial swing states on Monday, delivering their final arguments to voters on the last day of an extraordinarily close race for the White House.After a long, bitter and expensive campaign, national polls show Obama and Romney are essentially deadlocked ahead of Tuesday’s election, although Obama has a slight advantage in the eight or nine battleground states that will decide the winner.Obama plans to visit three of those swing states on Monday and Romney will travel to four to plead for support in a fierce White House campaign that focused primarily on the lagging economy but at times turned intensely personal.The election’s outcome will impact a variety of domestic and foreign policy issues, from the looming "fiscal cliff” of spending cuts and tax increases that could kick in at the end of the year to questions about how to handle illegal immigration or the thorny challenge of Iran’s nuclear ambitions.The balance of power in Congress also will be at stake on Tuesday, with Obama’s Democrats now expected to narrowly hold their Senate majority and Romney’s Republicans favoured to retain control of the House of Representatives.In a race where the two candidates and their party allies raised a combined $2 billion, the most in U.S. history, both sides have pounded the heavily contested battleground states with an unprecedented barrage of ads.The close margins in state and national polls suggested the possibility of a cliffhanger that could be decided by which side has the best turnout operation and gets its voters to the polls.In the final days, both Obama and Romney focused on firing up core supporters and wooing the last few undecided voters in battleground states.