Former Homeland Security chief Tom Ridge returned to his home state Thursday to stump for Republican Sen. Rick Santorum, saying the country needs his leadership as it contends with terrorist threats across the globe.

Ridge, a former Pennsylvania governor who resigned to be the first director of the Department of Homeland Security after the Sept. 11 attacks, urged voters to support Santorum over Democratic challenger Bob Casey even if they don't always agree with him.

Casey, rallying party faithful at a fundraiser in Williamsport, said Republicans were resorting to scare tactics in the closing days of a hard-fought campaign.

''If you want to know what's going to happen in the next five days, just look at the previous 10 days, or frankly for Rick Santorum, his entire campaign,'' Casey said. ''We're going to see fear and smear and divide and conquer.''