How can Obama beat McCain if he cant even win the big states, especially when Republicans rule them?

In the Democratic primary, the liberal vote was split between Obama and Hillary Clinton. In the general election, it won't be. So just because he didn't win a state in the primary doesn't mean he won't win it in the general election. In most elections there are lots of states that a candidate loses in the primaries, but wins in the general election. Like Bush and New Hampshire in 2000.