is now expected to become the next U.S. secretary of defense. To those who haven't followed the Senate closely in the past decade, he's probably not a household name. Hagel is a former GOP senator and Purple-Heart-decorated Vietnam veteran, but he wouldn't necessarily be a popular pick with Republicans in Congress. Here's why. The former Nebraska lawmaker has a long-running independent streak, one that made him an outsider within his own party by the time he left Congress in 2009, as he clashed with President Bush and Sen. John McCain of Arizona on foreign policy, most notably the Iraq War. Hagel fiercely criticized Bush's "surge" of 30,000 additional troops to Iraq, which Bush pursued against the bipartisan Iraq Study Group's proposal of a draw-down and regional diplomacy, preferred by Hagel. When Bush instead announced that more troops would go to Iraq, Hagel co-sponsored a nonbinding resolution to oppose it, along with then-Senator Joe Biden, D-Del. "I will do everything I can to stop the president's policy as he outlined it Wednesday night," Hagel said at the time. "The president says, 'I don't care.' He's not accountable anymore," Hagel told Esquire in June 2007. "He's not accountable anymore, which isn't totally true. You can impeach him, and before this is over, you might see calls for his impeachment. I don't know. It depends how this goes."