How bald are we talking here because many of our (U.K) Prime Ministers have had balding heads. Not totally bald but even current PM David Cammeron flicks his hair back to conceal his thinning hair at the top of his head. The Chancellor - Osborne - has a caeser cut to conceal receding. Tony Blair is very thin and whispy now. Callaghan, Wilson, Heath, Home, McMillan, Churchill, Clement Attlee (a proper NW7), Cecil, Gladstone and Disraeli - all NW3/diffuse thinners or more.
U.S. president is bizarre though - very image orientated.