Freshman Rep. Rick Berg (N.D.) made his Senate campaign official Monday, providing Republicans with a top candidate for retiring Democratic Sen. Kent Conrad’s seat. “To change Washington, we need to change the Senate,” Berg said in an online video announcement circulated to supporters. “Washington could learn a lot about the way we do things in North Dakota. Unfortunately, President Obama, Harry Reid and Senate Democrats have stopped real reforms. That’s why I’m running to be North Dakota’s Senator, to bring much-needed change to the Senate.” Republicans view Berg as a top candidate for the open Senate seat in 2012. Although...