Replaced by whom? The US foots the bill pretty much for defense of the entire modern world. This is one of the unspoken reasons other countries, can, barely afford their social safety nets. They contribute next to nothing for their own defense.
I cannot wait for the UN to leave. Yes, leave and begone and not come back and for the USA to keep our taxes for internal use. We have really bad infrastructure problems nationwide and we need to send US citizens to our own schools and kick out the people who are taking our citizens’ places especially the Diplomats’kids. It is time for the UN to be GONE!