Santa Barbara is about as far from Greenville, S.C., as you can get in the continental United States, but Sen. Jim DeMint (R-S.C.) cares more about principle than geography. He is leading a conservative insurgency across America. Speaking at the David Horowitz Freedom Center's annual retreat here late last month, DeMint told the faithful that if they want to return to the principles of limited government, they need to elect people who believe in limited government: "I came into the Senate with 55 Republicans, George W. Bush in the White House and large majorities of Republicans in the House, and...