Puerto Ricans will head to the polls Tuesday to answer a question that has long divided this island of four million people: Do they still want to be a U.S. territory?

It will be the fourth time in 114 years that such a poll has been taken. But while some politicians dismiss the electoral exercise as a pointless waste of time, both those who want to join the union and people who wish to abandon it believe this may be the referendum that finally forces Congress to take up a thorny issue it has traditionally avoided.

Experts say they shouldn’t count on it.

“This plebiscite is undemocratic and un-American,” said Héctor Ferrer, a spokesman for the Popular Democratic Party, which favors an enhanced version of Puerto Rico’s current commonwealth status.

A little history:

Puerto Rico has been part of the United States since 1898, when Spain ceded it in the Spanish-American War. People there are U.S. citizens who do not cast ballots in presidential elections or pay federal income taxes, but they enjoy social welfare perks such as Medicare. The island has a long history of military service but just one member of Congress — who does not vote.

When asked whether they’d rather become the 51st state or remain affiliated with the United States, voters have traditionally been at a stalemate. It’s always a dead heat between those two options, with a small minority of voters opting for an independent nation.

The last time a plebiscite was held, in 1998, Ferrer’s party did not like the ballot language, so “none of the above” finished first.

But this plebiscite is different. Instead of asking voters a multiple choice question in which no one answer would get a clear majority, the ballot asks: “Do you agree that Puerto Rico should continue to have its present form of territorial status?”

The difference is critical, because it unites the voters who prefer statehood with those who want independence. Together those two forces could form a majority to answer “no,” which would then force the second question.

It asks voters whether they want statehood, independence or a “sovereign free associated state,” where Puerto Rico would be an independent nation with ties to the U.S. (Part two of the plebiscite would only be valid if the majority voted no on the first question.)

The Popular Democratic Party balked because none of the options on the ballot quite reflect what they promote for Puerto Rico, which is an enhanced version of what the island has now. Since “none of the above” is no longer one of the choices, the party is asking voters to say “yes” on the first question and skip the second.

Critics argue that the deck was unfairly stacked toward statehood and was deliberately designed so that the party that usually wins is left out.

“It’s clearly a political play by the government in power to promote its agenda,” said Jorge Duany, a longtime University of Puerto Rico professor who now runs the Cuban Research Institute at Florida International University. “It’s extremely biased and does not reflect the consensus. If you don’t include the Popular Party, you are missing half the population.”

Ferrer said it was really just a mobilization ploy by the governor, who is running for reelection and needed a gimmick to get his people to the polls. Gov. Luis Fortuño dismissed the criticism, saying it was impossible to reach a consensus with a party that refused to participate in the process.