DENVER (AP) - One of the main themes at this week's Democratic Convention is "unity," and in keeping with that theme Hillary Rodham Clinton is expected to release her pledged delegates and encourage them to support Barack Obama.

But not all of her delegates think that's a good idea.

John McCain has a new a TV ad featuring a former Clinton delegate who now backs McCain over Obama. Debra Bartoshevich says, "A lot of Democrats will vote McCain." She adds, "It's OK, really!"

An Obama spokesman this morning acknowledged on NBC's "Today" show that a lot of delegates were passionate about their choices in the primaries. But Robert Gibbs says he's confident that Obama will have their support in November.

(Copyright 2008 by The Associated Press. All Rights Reserved.)