It's not Bush's popular vote total alone, though given the way the electoral college works there are many states where people who think Bush is doing a good job don't need to vote, but a general shift. When I first visited the US in 1998 I remember a number of commentators noting the way that the country was shifting Republican - an article on Governors was hard pressed to think of a notable non-Republican one for instance.

For the first time since at least the 1930s the Democrats do not control any organ of government - not the White House, not the House of Representatives, not the Senate. They are increasingly on the defensive, have very few potential Presidential candidates for next time (why people think Hilary Clinton is the person to retake the mid west I have no idea), are riven by potential splits that only held off due to the "Anyone But Bush" campaign and do not look like winners for the foreseeable future.

It may have been a close Presidential election, but this doesn't look like an abnormal blip. America has lurched to the Bush Republicans and seems likely to stay there for the moment.