Democrat Barack Obama pushed deep into Republican turf on Friday and forced rival John McCain to play defense on traditionally friendly ground as the US presidential race headed into a frenzied final two weeks. Obama launched a four-day tour of Virginia, Missouri, North Carolina and Florida, all states won in 2004 by President George W. Bush that could be on the verge of tipping to the Democrats. Victories there – or in any one of a long list of other states won by Bush including Ohio, Colorado, Nevada, Indiana or West Virginia – would likely give Obama the 270 electoral votes he needs to capture the White House in the Nov. 4 election. Obama's surge in opinion polls as the economic crisis intensified has left Republican McCain hoping to cobble together wins in the same coalition of states that gave Bush a narrow victory in 2004. “There is really only one realistic alternative left for John McCain, and that is to carry enough of the Bush states to win,” said Peter Brown, assistant director of the Quinnipiac University poll. “At this point McCain is not in a position to win any Democratic state from 2004 and Obama has opportunities all over the map,” Brown said. McCain's dilemma is evident in his travel schedule. Aside from a stop on Thursday in Pennsylvania, won by Democrat John Kerry in 2004 but where he trails now by double-digits, he is concentrating on defending states won by Bush in 2004. McCain will hit Florida, North Carolina, Virginia, Ohio and Missouri over the next four days, all Republican-held states in 2004 where Obama threatens a key breakthrough. If Obama holds all of the states won by Kerry in 2004 and recaptures the Bush states of Iowa and New Mexico – he leads comfortably in all of those – he will be just six electoral votes shy of the 270 he needs to win. West Virginia in play Obama has profited from a huge spending advantage over McCain and has flooded airwaves with ads in key states. He even began advertising on Thursday in West Virginia, a Bush state that was considered safe McCain ground until recently. Obama advisers said the growing economic concerns of working-class voters have made them more receptive to the Illinois senator, who polls show is favored on economic issues. In West Virginia, the spillover of ads from television stations in neighboring swing states that can be seen there have helped put that state in play. “Every day McCain's very narrow path to the presidency is getting more narrow,” Obama adviser Robert Gibbs said. “The battlegrounds left in this election are states that George Bush carried at least once and mostly twice, and that gives us a real opportunity.” McCain aides said there are more than enough states up for grabs for the Arizona senator to hit 270 electoral votes, and they are looking for every possible angle to hit the magic number. Alaska Gov. Sarah Palin, McCain's running mate, visited Maine on Thursday, one of two states that awards its electoral votes by congressional district rather than giving them all to the statewide winner. Republicans hope McCain and Palin can snare one of the state's electoral votes in northern Maine, where moose-hunters and snowmobilers give the cultural climate a similarity to Alaska. “The senator and the governor will use every opportunity they can to contrast the real differences,” with Obama as the campaign concludes, McCain campaign manager Rick Davis said. “We all look forward to the next 18 days.” Some recent tracking polls have shown a slight improvement in McCain's standing nationally in the last few days. The latest Reuters/C-SPAN/Zogby poll gives Obama a 5-point edge, and a Gallup poll on Thursday put the margin at only two points in one sample. Another tracking poll sponsored by the political news site Hotline, however, showed Obama expanding his national margin on Friday to 10 percentage points. “McCain could gain three or four points in the polls over the next few weeks, but that doesn't mean the race is tightening up,” said Simon Rosenberg, head of the Democratic advocacy group NDN. “The question is whether Obama also gains three or four points with those last undecided voters,” he said. Obama warned supporters against overconfidence on Thursday, putting the message in particularly stark terms when he spoke at a concert to benefit his campaign by rock legends Bruce Springsteen and Billy Joel. “Don't underestimate the capacity of Democrats to snatch defeat from the jaws of victory,” Obama told about 2,000 rocking donors in New York's Hammerstein Ballroom. “Don't underestimate our ability to screw it up.” – Reuters __