Anti-ballistic missiles : don't worry, be happy (1954-71) -- The strategic defense initiative : much ado about very little (1972-85) -- Global protection against limited strikes : too close for comfort (1986-92) -- National missile defense : let sleeping dogs lie (1993-2000) -- Ground-based midcourse defense : is this the end? (2001-05) -- Forward to the past (2006-beyond).