In a sense, you could say that Trump’s policy towards Ukraine has been a success; he has passed the responsibility for arming and financing the Ukrainian government to the EU without causing disruptions that changed the trajectory of the war. But was that really his objective?
The problem with “America First” is that it ultimately forces the rest of the world to become independent of you. What Trump really wanted was to impose his will on both Ukraine and the EU in the manner of an organized crime boss, not simply to reduce American costs. The Ukrainian government is already showing far less inclination to suck up to him, and the EU will follow. Then what?
The loss of American influence, of course.