SUPERDELEGATE UPDATE

From NBC's Domenico Montanaro
The Obama campaign announced Christine "Roz" Samuels, a DNC member and superdelegate from New Jersey, switched her support from Clinton to Obama. NBC News can confirm that Samuels had been supporting Clinton.

This also changes the superdelegate count more so than just a usual pick up because, in baseball terms, it helps in both the win and loss columns.

The NBC News Political Unit superdelegate count now stands at Clinton 260, Obama 181. This brings Obama's post-Feb. 5 superdelegate endorsements to 11-2 over Clinton. (And Clinton's lost two, including Samuels and Tom Lantos, who passed away.) Super delegate numbers reflect totals gathered by the Political Unit from the campaigns and public endorsements.

The Obama campaign also announced the endorsement of former Republican Sen. Lincoln Chafee, of Rhode Island. Chafee switched his party affiliation to independent after losing his seat to Democrat Sheldon Whitehouse, who is supporting Hillary Clinton. Rhode Island holds its primary March 4.