Republicans are hitting Barack Obama personally, suggesting that he hasn't shown Americans who he really is -- and, of course, that the real Obama is scary and un-presidential, even un-American.

While campaigning in New Mexico today, John McCain himself let loose a particularly caustic attack on Obama. Not to be outdone by his running mate, the Republican presidential nominee said:

Even at this late hour in the campaign, there are essential things we don't know about Senator Obama or the record that he brings to this campaign.

My opponent has invited serious questioning by announcing a few weeks ago that he would, quote -- "take off the gloves." Since then, whenever I have questioned his policies or his record, he has called me a liar.

Rather than answer his critics, Senator Obama will try to distract you from noticing that he never answers the serious and legitimate questions he has been asked. But let me reply in the plainest terms I know. I don't need lessons about telling the truth to American people. And were I ever to need any improvement in that regard, I probably wouldn't seek advice from a Chicago politician.

My opponent's touchiness every time he is questioned about his record should make us only more concerned. For a guy who's already authored two memoirs, he's not exactly an open book. It's as if somehow the usual rules don't apply, and where other candidates have to explain themselves and their records, Senator Obama seems to think he is above all that. Whatever the question, whatever the issue, there's always a back story with Senator Obama. All people want to know is: What has this man ever actually accomplished in government? What does he plan for America? In short: Who is the real Barack Obama? But ask such questions and all you get in response is another barrage of angry insults.

It's not new for a conservative politician to suggest that the place from which their opponent hails affects what they say. But this seems like more. When McCain asks, "Who is the real Barack Obama," and later says, "You need to know who you're putting in the White House -- where the candidate came from and what he or she believes," he appears to be attempting to use the scurrilous rumors and fears about Obama for his own political advantage. To underscore the point, check out the video below (h/t Marc Ambinder) of the reaction to McCain's remarks. When McCain asks, "Who is the real Barack Obama," one member of the crowd shouts, "Terrorist!"