Sen. Ben Nelson (D-Nebraska) is announcing today that he's retiring after two terms, dealing a blow to Democratic efforts to hold their majority next November. The 70-year-old senator had already been targeted by hundreds of thousands of dollars in TV ads from GOP-affiliated groups. Nelson, one of the most moderate Senate Democrats in his voting record, supported the Bush tax cuts in 2001, yet also backed President Barack Obama's $787 billion stimulus package in 2009 and health reform.
