I don't know if I'd phrase it as the "power" to do whatever it wants.

Anyone can always do whatever they want. And the only way there aren't repercussions on some level are if you're some kind of god-like being sealed in the equivalent of closed terrarium.

Does the US have power? Sure. But the US could act disgracefully even if it didn't have power.

The framing I'd give this is that the US is trying to extort Ukraine without actually bringing anything to the table, and all it's going to accomplish is making the US itself less powerful, less reputable, the rest of the world more convinced that nuclear weapons need proliferate because otherwise invasions are on the table, and a litany of other things that will basically make the US weaker over time.