Liberals consider themselves as almighty. This perception allows them to claim they are never forced to do things because of circumstances.
The fact is they were forced to set this deal in order to avoid facing heavy cost. They were failing to achieve the goals of the war, that is eradicating or displacing Palestinians and at this stage, the US world order was jeopardised.
Many ways to see this, one is the UN.
For years, Trump was used to rant about the UN, threatening to leave etc
The last summit that happened before the deal, Trump praised the UN and assured it had the full support of the US.
The reversal is easy to explain. Trump was never serious about leaving the UN that matters too much in spreading US influence over the world (his grudge against the UN came from a real estate project the UN refused him)
On the other hand, the rest of the world wants either to get rid of the UN or to strongly change it.
And in this war, without the UN, the US and Israel could not have sustained their war for so long.
The UN is what has allowed Israel and the US to keep that war going. In a different organisation, with a diminished US influence, it is likely that the war would not have lasted that long.
The evolution of the vote showed that the UN was what allowed it to happen. The last resolution showed that this had turned into Israel and the US against the rest of world. They were the only two countries that voted against the resolution, apart from ten very minor countries that have no weight.
The situation was such that the US had to save the UN because it was made clear that the UN could not work a peace resolution because of the US influence. The rest of the world was in a situation they could have taken the step forward.
The deal exists to serve Israel and the US's best interests first. The irony is that the US had to seal a deal outside the UN to keep it working as it is.
It is one of the many costs the US were not to face.