The true sign of lameness in a Presidency is when, as the end of his term in office is coming to a close, key officials and aides start to resign in order to "enter private business" or "spend more time with family." Why not see it through to the end? Money. A former White House staffer or cabinet member is much more valuable to a lobbying firm or government contractor if that person still has contacts within the Executive branch. It's old fashioned palm greasing.
With today's announcement that Dan Bartlett is resigning effective July 1, I think we can safely declare this president lame.