Click on the above link to understand why the government of the United States can't be in charge of the decolonization of Puerto Rico.
Puerto Rico is a colony of the United States (US) since 1898, because the US invaded Puerto Rico to have it that way. It is ridiculous to believe that the government of the United States will reverse a political relationship that unilaterally was set up by itself. What would be the US' motivation?
Once the United Nations (UN) determined that colonialism is a crime against humanity because it is a threat to world peace, it doesn't matter what the Puerto Ricans or the United States government think. All these plebiscites to find out what people want are totally unnecessary. These plebiscites are used to continue to divide Puerto Ricans so that the government of the United States can continue to maintain the colony of Puerto Rico forever. This is why the US government has ignored 33 UN resolutions to immediately decolonize Puerto Rico, and refuses to release Puerto Rican political prisoner of 33 years Oscar López Rivera.
If the US government really wants to decolonize Puerto Rico, all it has to do is to ask the UN to do it consistent to international law. That way the entire process would be transparent, and its validity would not be challenged. But, the US prefers to do it in the most controversial manner possible, so that everything locks up and what is left is the status quo which is what it wants. That's where we have to push together really hard to get this in the right venue.