One of the top Democrats in the House endorsed Barack Obama's presidential campaign Tuesday, bringing near the end of the Democratic nomination race as the last two states cast their votes.

Rep. James Clyburn (D-SC) announced his endorsement on the Today Show Tuesday, as voters were preparing to cast their ballots in South Dakota and Montana -- two states Obama is expected to win. Hillary Clinton faces a virtually insurmountable deficit in the Democratic delegate count, and speculation is mounting that she will suspend her campaign soon.

The endorsement from Clyburn -- the third ranking member of the Democratic  leadership and top ranking black lawmaker -- is expected to open the door for other members of Congress to endorse Obama.

Clyburn said he didn't announce an endorsement earlier to avoid injecting himself into the nominating process. Backing Obama now, though, is "what's best for the party," he said.

A partial transcript of Clyburn's discussion with Today Show host Matt Lauer is below:

CLYBURN: I've decide to cast my delegate ballot for Senator Barack Obama. I think that, as I watch this campaign unfold, he is elevating the political rhetoric. He's elevated our party. He's energizing our country. He is bringing to the process new voters, young voters, older voters, people who are in thirst of a new vision for our country.

LAUER: Let me ask you, though, Congressman Clyburn, by waiting before this is almost a foregone conclusion, I think it begs the question, a fair question, is this about a heartfelt feeling that he's the right man for the job or is this about being a realist and doing the math?

CLYBURN: It's about doing what's best for our party. I stayed out of this process because I didn't want to inject myself as other superdelegates did not want to inject themselves into the process. Today, the process ends and I hope that enough of us will announce our intentions today so that this evening our candidate, our nominee, presumptive nominee, will be able to credit the voters of this country with having achieved a threshold of 2,118 rather than giving that credit to inside the beltway folks like myself.

With wire reports

This video is from NBC's Today Show, broadcast June 3, 2008.

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