The Commonwealth of Puerto Rico voted for statehood on Sunday, but virtually no one expects it to join the union anytime soon.

Only about 23% of eligible voters turned out for the election, and 97% of them voted for statehood.  But opposition parties that favored independence for the island or a maintenance of the political status quo urged their supporters not to participate in what they called a "rigged" election.

CNN:

Congress, the only body that can approve new states, will ultimately decide whether the status of the US commonwealth changes.

"It will be up to this new generation of Puerto Ricans to demand and claim in Washington the end of the current improper colonial relationship, and begin a transition process to fully incorporate Puerto Rico as the next state of the Union," Governor Ricardo Rosselló of the pro-statehood New Progressive Party said in a statement Sunday.

For Puerto Rico to become a US state, Congress would need to pass a statute laying out the transition process. If Congress does not pass a statute, Puerto Rico's status will remain as it is.

Options on the weekend referendum included remaining a commonwealth, becoming a state or entering free association/independence. Free association is an official affiliation with the United States. Typically it would include Puerto Rico still receiving military assistance and funding but the ballot says the terms would be agreed upon by the two countries as sovereign nations.

The island picked a horrible time to ask to become the 51st state.  It has all but declared bankruptcy due to its massive $70-billion debt.  More than a third of island residents participate in the SNAP food stamp program, and unemployment is a whopping 14%.  Both capital and people have been fleeing the island for years, leaving Puerto Rico impoverished.

But with this vote, the governor will appoint two senators and seven representatives who will show up in Congress later this year and demand to be seated.  It's called the "Tennessee Plan" and was successfully employed by seven former U.S. territories to effect statehood.  Congress originally organized the land that is now Tennessee into a territory with the understanding that it would eventually become a state.  But the process was too slow for many in the territory, and they took several steps to force statehood on the U.S. Congress:

They held a vote and 73% of the people voted for immediate statehood. The Governor and the local legislature held a convention to establish a constitutional government – not as a territorial government but for government as a State of the Union. The convention approved a state constitution, declared the end of territorial government on March 28, 1796, and said Tennessee would become a State on that same day.

The legislature also established two Congressional districts, authorized four presidential electors, sponsored elections for two members of the U.S. House, and elected two Senators. The U.S. Senate opposed admission; Tennessee was being too bold for them. The Tennessee Senators went to the Senate and demanded their seats, but the Senate refused.

The House supported admission, though. On June 1, 1796, Congress yielded and passed an admission act allowing Tennessee one seat in the House until the next census. They also insisted on new elections, since the citizens of a territory did not have the  power to elect members of Congress.  Only citizens of a state can do that. Tennessee had declared itself a state, but only Congress can do that.

Tennessee accepted the compromise and became a state just a few months after they said they would.

Republicans in Congress are not eager to add another reliable Democratic state to the union with another seven electoral votes for the Dems.  They also are balking at the idea of bailing out the island and fixing its debt situation.

In short, it is extremely likely that any plan by Puerto Rico to effect statehood is dead in the water as long as Republicans own a majority in Congress.