The Obama administration often cites Colombia’s thriving democracy as proof that U.S. assistance, know-how and commitment can turn around a potentially failed state under terrorist siege. The country’s U.S.-funded counterinsurgency campaign against a Marxist rebel group — and the civilian and military coordination behind it — are viewed as so successful that it has become a model for strategy in Afghanistan. But new revelations in long-running political scandals under former president Alvaro Uribe, a close U.S.