Ridge, a former two-term Pennsylvania governor, served as first head of the nation's newly created Department of Homeland Security from 2003 to 2005. He praised McCain's leadership in a statement announcing his support for the Arizona senator's bid for the White House:
"What sets John apart is his ability to form coalitions around a common, principled cause. Our country is at a crossroads and John McCain is the leader who fundamentally knows what it takes to move us forward and keep us safe," Ridge said.
McCain, who is expected to formally enter the race for the 2008 GOP nomination in March, said that Ridge's "expertise as an innovative governor and national leader ... is invaluable and I'm grateful for his support."
McCain, once seen as the Republican front-runner, has been leading the GOP presidential field in endorsements, but increasingly lags behind former New York City Mayor Rudy Giuliani in polls of Republican voters.