Recently declassified documents reveal that consideration of how and when the White House can or should pressure Israel over policies damaging to the United States has been a contentious issue for quite some time. The 107 pages of formerly top secret memos, dating from 1968-9, relate to deliberations over what to do about the Israeli nuclear weapons programme. Prior to that time, the US position had been clear, supporting the principle that nuclear weapons should not be introduced into the Middle East.