A new poll shows Sen. Mitch McConnell with a precarious lead over potential Democratic challengers.The survey from Public Policy Polling shows McConnell with a four point lead over Secretary of State Alison Lundergan Grimes—45 to 41—and a five point lead over former Congressman Ben Chandler.Despite the leads, McConnell polls below the 50 percent mark in both races. And it shows he only has an 11 point lead over contractor Ed Marksberry, 46 to 35. And the poll results show only 34 percent of voters approve of McConnell, while 54 percent disapprove. Those are similar to previous number PPP had on McConnell's approval ratings. McConnell's campaign blasted the poll results, calling the numbers cooked by a Democratic polling agency. And it maintained McConnell was strongly situated for his re-election.