The latest CNN poll finds Democrats are leading Republicans by three points—45% to 42%—in a generic match-up for control of Congress. That’s a better position for Republicans compared to CNN’s previous poll in March when Democrats were up by six points. Experts say a three-point lead usually translates into a 10 to 15 seat turnover. But the shrinking number of truly competitive seats and the redistricting wars complicate the picture. CNN’s data guru Harry Enten said yesterday that a three-point lead now might not be enough to flip control of the House.