BREAKING: Sources close to Rep. Michele Bachmann tell National Review Online that Keith Nahigian, a top advance man on the campaign, will take over as campaign manager, following the departure of Ed Rollins from that post. Rollins, as a senior adviser, will continue to play an important role in devising the campaign’s big-picture strategy. Both Bachmann and Rollins work closely with Nahigian, sources say, so the decision to insert Nahigian into that position was easy, and one they made together, once Rollins decided to step down.