Apparently completely unworried by the sharp drop in his support in polls nationally and in early primary states, John McCain vows to fight on. Jim Davenport reports for the Associated Press:

Republican presidential candidate John McCain on Monday dismissed polls that show him slipping into single digits, arguing that his campaign is going through the typical ups and downs and will be fine this fall.

In an interview with The Associated Press, the Arizona senator also defended his support for a bipartisan immigration bill, a stance that has undercut his bid in early voting South Carolina.

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"With the core support we have, we're going to do fine. We're going to do fine," McCain said in the interview, adding: "You watch in September."

Read the whole story at the link above. Is McCain promising poll improvement by September? Heck, a lot of folks are predicting he will be OUT by then . . . and if not rising poll numbers, what possible event in September could improve his chances? He isn't participating in the August Ames Straw Poll in Iowa, which would seem the only other major way to generate a major boost between now and the fall.

McCain won 42% of the vote here in SC in 2000, but there were an awful lot of Democrats crossing over to vote for him (no party registration in SC; you can vote in either party primary, but not both) that year when the Democratic nomination was not at issue, probably to damage or slow down Bush more than to support McCain. There is a hot 'n' heavy battle going on in the Democratic Primaries this year, though, so most of those voters probably will not cross the line for him this time around - as the polls are bearing out.

I respect Senator McCain a great deal, but he is the most well-known figure in the Republican nomination race. It's hard to see him gaining sudden momentum - unless all the candidates ahead of him fall apart or suffer scandals between now and then.

Knowing McCain's penchant for playing rough, it wouldn't surprise me in the least to see dirt about Giuliani, Romney, and Thompson hitting the fan soon. It better be good stuff, though, because McCain is in a very deep hole right now. His support is falling in almost every state and national poll (except ARG, which seems to have an affinity for him not verified by any other established poll), and for a candidate as established as McCain, that is very bad news.