Those on the left side of American politics who were aghast at the idea of a US President moving the American Embassy to Jerusalem might be surprised to know that the idea that the US has the absolute right to do so was enunciated under the Carter administration.
UNSC 478 (1980) , along with condemning Israel for annexing Jerusalem, called upon "Those States that have established diplomatic missions at Jerusalem to withdraw such missions from the Holy City."
Even though the US shamefully abstained from vetoing that anti-Israel resolution, US Secretary of State Edmund Muskie forcefully rejected the dictate from the UN:
[T]he Council calls upon those States that have established diplomatic missions in Jerusalem to withdraw them from the Holy City. In our judgement this provision is not binding. It is without force. And we reject it as a disruptive attempt to dictate to other nations. it does nothing to promote a resolution of the difficult problems facing Israel and its neighbours. It does nothing to advance the cause of peace.
So the US maintained the right, if it should ever want, to establish the US embassy in Jerusalem.
One other thing. During the debate on Friday, a number of ambassadors stressed that all countries withdrew their embassies from Jerusalem after the 1980 UNSC resolution, emphasizing how the US would now be breaking an international consensus.
But the language of UNSC 478 was not about embassies, but about any diplomatic missions.
And here's a list of countries with consulates in Jerusalem:
Belgium, in East Jerusalem
France in West Jerusalem
Greece in West Jerusalem
Holy See (Apostolic Delegation to Jerusalem and Palestine) in East Jerusalem
Italy, with seats in both East and West Jerusalem
Spain, in East Jerusalem
Sweden in East Jerusalem
Turkey in East Jerusalem.
United Kingdom in East Jerusalem
United States, in West Jerusalem
Many of these provide services for Palestinians, but UNSC 478 doesn't have an exception for those cases. It calls on any nation with diplomatic missions in Jerusalem to withdraw them. Period.
So when France, Sweden, the UK and others spoke at the Security Council on Friday and invoked UNSC 478 as a UN resolution that the US was breaking....they are breaking it, too. Every day.