Trump's repudiation of internationalism doesn't stop with border walls.
The new administration has drafted drastic executive orders that would pull funding from the United Nations and potentially pull the US out of the Paris Agreement, causing alarm at international organizations that wonder if their operations (including health, peacekeeping, and development) can continuee without US funding.
While the orders use Palestinian membership as the reason for ceasing funding, it seems more likely that is an excuse for a general turn away from internationalism.