"A behind-the-scenes battle broke out late Tuesday over superdelegates who had secretly committed to Sen. Barack Obama (D-Ill.), with Clinton campaign officials scrambling to “freeze” them before they announced support for him.
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Democratic officials involved in the conversations said Obama was lining up a package of superdelegates – the party insiders whose votes help select the Democratic nominee – with plans to announce their support as a bloc.
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But aides to Sen. Hillary Rodham Clinton (D-N.Y.) became convinced by network exit polls and her own data that she would have a stronger-than-expected showing. So they immediately began urging Obama’s prospective superdelegates to withhold their support....One Democratic lawmaker described “pushback” from the Clinton campaign, but did not elaborate.
A senior Clinton aide said her supporters were scrambling to "freeze" members of congress on the verge of announcing for Obama, and said a good night for Clinton would be key to forestalling the move."
http://www.politico.com/news/stories/0308/8838.html