With the presidential election four days away, Democratic candidate Barack Obama has clutched or boosted his lead in four key states won by President George W. Bush in 2004—Nevada, North Carolina, Virginia and Ohio, according to Time.com. The polls are conducted by Opinion Research Corporation. Obama made the most headway in North Carolina and now leads his Republican rival John McCain among likely voters by a 51 percent to 47 percent margin. The Illinois senator also expanded his lead to 51 percent to McCain's 46 percent in Nevada. In the most pivotal swing state of Ohio, presidential hopeful Obama leads the Arizona senator by a gap of 50 percent to 46 percent. Despite Obama's ability to take continuous leads in red states, he still has some setbacks. He lost pull in West Virginia and now lags behind 41 percent to McCain's 53 percent.