DO IT!
Just look at the TPP. The US tried to write the rules and the rest of the partners said, "No." The US said, "Screw you guys, we're going home!" and stormed off in a snit assuming the deal would fall apart without them but it didn't and it ended up being better without the US imperialist bullshit. Then, US farmers realized that they were getting fucked because the US wasn't part of the deal ([1], [2], [3]) and the US came back demanding to be let in and the US imperialist bullshit restored to the agreement. Once again the partnerd said, "No".
Let's let the US leave whatever they want to leave, renegotiate everything without them, then only let them return under the new terms. The world will be a much better place in the end.
EDIT: Trump ordered the US to withdraw from the TPP because the partners wouldn't be bullied into accepting one-sided andi-competitive, anti-consumer protections for US industry and a dispute resolution process that favoured the US but that the US would ignore when it lost.