> USA was neutral (with lots of Argentinian sympathy) until their hand was forced.
Ronald Reagan and Margaret Thatcher: A Political Marriage would disagree with you. Reagan wanted to keep the USSR out of Argentina so the public line was neutrality even with Thatcher pushing him to do otherwise. Behind the scenes the US provided intelligence to Britain.
The USA was, at least at first, divided on the issue and didn't exactly come swingeing down on the British side - many members of the Reagan administration thought that aiding the UK would hamper their anti-communist efforts in South America generally and I guess as hegemon they just wanted the whole inconvenient problem between two US allies to go away.
Later when it became clear that the UK was going to war, that was that. They did support the British position but didn't get entangled publicly for their own reasons, not least there's no point getting involved if your ally can take care of it anyway.
Ronald Reagan and Margaret Thatcher: A Political Marriage would disagree with you. Reagan wanted to keep the USSR out of Argentina so the public line was neutrality even with Thatcher pushing him to do otherwise. Behind the scenes the US provided intelligence to Britain.