Faced with an intractable situation, the British shrugged their shoulders and handed the mandate to the UN to resolve, who then voted for partition, which the USA was in favour of. So that's one thing you've been dishonest about.
The US withdrew their support for partition when the civil war of 1947 made it clear that the solution being presented wasn't going to work.
Trumann ended up voting for the partition he didn't support (and he told the lobbiest he didn't support it at all) because, in his own words -
The facts were that not only were there pressure movements around the United Nations unlike anything that had been seen there before, but that the White House, too, was subjected to a constant barrage. I do not think I ever had as much pressure and propaganda aimed at the White House as I had in this instance. The persistence of a few of the extreme Zionist leaders—actuated by political motives and engaging in political threats—disturbed and annoyed me."