This is shaping up as a presidential election designed to Donald Rumsfeld’s specifications. At a 2002 press conference during the run-up to the disastrous Iraq War, George W. Bush’s hawkish defense secretary began talking about “known unknowns,” which he defined as things “we know . we do not know.”In an election that offers the first rematch between an incumbent president and his predecessor since 1912, the campaign tactics and TV advertising blitz by both sides are likely to be dwarfed by a