The U.S. needs new nukes. That's the message Pentagon chief Robert Gates is delivering right now, as part of a broad, spirited defense of America's nuclear arsenal.

Congress and the Bush administration have been wrestling for years over the so-called Reliable Replacement Warhead — the next generation of nuclear weapon designs. Lawmakers have had the upper hand in the match, eliminating funding for RRW. Today, in a speech to the Carnegie Endowment for International Peace, Gates looks to scramble back on top, with a dire warning to Capitol Hill.