Is the US exiting NATO and the United Nations? This speculation has gained momentum after Trump's “First Buddy” Elon Musk share support for the same on X, formerly known as Twitter. Some Republicans have also expressed interest and willingness for the USA to leave
NATO.

These conjectures have come around at a time when America's global power is being discussed and continuously challenged. Before the fall of the USSR, the world was bipolar meaning, there were two primary powers. After the fall, it became unipolar where America's authority could not have been challenged, and it was the strongest nation-state in the global arena. However, today the world is changing again, it's forming new alliances, new poles, new partnerships. The world has largely been multipolar from 2015 onwards, with Asian powers providing a strong base to potentially contest the Western hemisphere.

Moreover, leaving NATO would significantly impact the world as well. Since nations like Russia, China, and South Korea have constantly been stopped by the USA’s influence, they'll exert their global power and NATO would significantly grow weaker in the event of America's absence.
Only time will tell if the Western Hemisphere is still as important as it was a few decades ago or if has it lost its luster.