History Today has an Archie Brown review of Reagan and Thatcher: The Difficult Relationship by Richard Aldous:
… Thatcher had serious reservations about Reagan’s Strategic Defence Initiative project (SDI — soon popularly referred to as ‘Star Wars’). In particular she rejected his idea that this hypothetical anti-missile defence system would make nuclear weapons — and the concept of deterrence — obsolete. When, at the Reykjavik summit in 1986, only Reagan’s determination to continue with SDI prevented his agreeing with Mikhail Gorbachev on a plan for total removal of nuclear weapons from global arsenals, the British prime minister became incandescent with rage.
Her strong attachment to nuclear weapons as a deterrent, in the belief that they would never be used, went alongside a foreign policy that was less bellicose than her popular image might suggest. Thatcher’s willingness to use force to take back the Falkland Islands, following their takeover by Galtieri’s Argentina, should not obscure her extreme reluctance to endorse military intervention where there had been no external attack on Britain or on a British dependency. Aldous cites her clearly-expressed opposition to military interventions for the sake of ‘regime change’:
We in the Western democracies use our force to defend our way of life … We do not use it to walk into independent sovereign territories … If you’re going to pronounce a new law that wherever communism reigns against the will of the people, even though it’s happened internally, there the USA shall enter, then we are going to have really terrible wars in the world.
That was provoked by the American invasion of Grenada to reverse an internal coup. Thatcher also took a sceptical view of American military strikes in Lebanon and Libya, saying: ‘Once you start to go across borders, then I do not see an end to it and I uphold international law very firmly’.
