Leader of the world? Nobody with an IQ over 40 would follow Biden out of a burning house.
I think everyone is misunderstanding him. I think he means he wants Biden to lead the world in what Zelinsky sees as the right and proper way with regard to the war. As in, Biden should give him more help, or something.
I don’t think he means he wants Biden to be the leader of the world in all matters, all the time.