Romney made his claim in April 2007, saying that, "Following the end of the Cold War, President Clinton began to dismantle our military. He reduced our forces by 500,000. He retired almost 80 ships. Our spending on national defense dropped from over 6 percent of GDP to 3.8 percent today."
The two Republicans are correct that military forces were reduced significantly under Clinton. The active-duty military totaled 1.8-million at the start of his presidency in 1993 and declined to 1.4-million in 2000. They are also correct that the naval fleet shrank dramatically. The Navy had 454 ships in 1993, but as vessels were retired and not replaced, the fleet was down to 341 by 2000.