The US is not isolated. Rather than relying solely on our European allies, the US has spent years developing strong relationships, allies with others. Countries that have strong military capabilities.
European countries have involved into an isolated island. They bicker among themselves, and publicly announced their military weaknesses and failure to invest in defense. They've not developed strong relationships with non European countries.
The United States is a world leader. The United States has the most nuclear weapons. The United States has the most powerful army on Earth.
Most countries value a relationship with the United States. Zelensky did not.
en.wikipedia.org
Moo