I know "empire" is maybe an outdated term but I'm just illustrating there are bigger incentives than at the national level. Ironically it is conservative nationalists (who are hated by the Left) that want the empire to shrink and for the US to pull back from this leadership position. The risk here is it could also destabilize the entire world, but that's a different matter.
In short, this move is an attempt to strengthen the status quo that began after WW2.If the status quo is maintained it directly benefits the US.