Sen. John McCain (R-AZ) won Florida’s Republican primary (MiamiHerald) in a contest that could hold major implications for the Republican nomination. McCain won 36 percent of the vote to Mitt Romney’s 31 percent and Rudy Giuliani’s 15 percent. The New York Times reports McCain’s win could be especially damaging for Giuliani’s campaign and says the former New York mayor is likely to endorse McCain.

In tough campaigning against Romney, McCain stressed his national security experience (WSJ) and asserted his leadership on supporting last year’s “surge” in Iraq. Exit polling of voters showed McCain did markedly better with voters putting the war as their top concern. He also bested Romney, who is campaigning as a business and finance expert, among voters placing the economy at the top of concerns (NYT). Exit polling logged by CNN showed 47 percent of Republicans said the economy was the most important issue. That far exceeded terrorism (19 percent), illegal immigration (17 percent), and the war in Iraq (13 percent).

On the Democratic side, Sen. Hillary Clinton (D-NY) won a comfortable majority of votes over her main competitor, Sen. Barack Obama (D-IL), Florida, but the vote will not count for any delegates (WashPost). The Democratic Party boycotted the Florida primary months ago for moving up its primary date. Attention now moves to the February 5 “Super Tuesday” primaries in more than 20 states.