On the eve of the first of two hearings to pick the best way for Puerto Ricans to determine their future relationship with the United States, two experts on island matters said a potential plan to let Puerto Rico develop as a commonwealth is unconstitutional.

The House Natural Resources subcommittee on insular affairs will host a hearing today on a pair of measures designed to address Puerto Rico’s territorial status, a sign, observers say, the issue could move forward in this Congress.

Puerto Rico has been a U.S. territory since 1898, and islanders gained U.S. citizenship in 1917. But their future has been debated ever since, as Puerto Ricans have fought in U.S. wars but can’t vote for president and lack full Congressional representation.

One proposal, offered in a bill introduced by Reps. Nydia Velázquez (D-N.Y.) and Luis Gutierrez (D-Ill.), calls for Puerto Ricans to host a constitutional convention, during which they would decide whether to become a state, declare independence or create a new or modified commonwealth.

Supporters, who include Gov. Aníbal Acevedo Vilá (a proponent of commonwealth), argue the measure would allow Puerto Ricans to study all the available options for the island’s future.

But former Puerto Rico Attorney General José Fuentes and Jeffrey Farrow, the co-chairmen of former President Bill Clinton’s Interagency Group on Puerto Rico, said Wednesday that commonwealth plans put forth by Acevedo Vilá’s Popular Democratic Party are unconstitutional.

Those plans would make Puerto Rico an autonomous political body tied to the United States for things such as common defense and U.S. citizenship. But the island would retain powers over fiscal autonomy and economic development as well as enter into commercial and tax agreements with other countries, Farrow said.

Farrow and Fuentes instead back a bipartisan measure introduced by Puerto Rico Resident Commissioner Luis Fortuño (R) and Rep. José Serrano (D-N.Y.) that would create a two-part, federally sanctioned self-determination process based on recommendations included in a December 2005 Bush administration task force report.

Arguing for that bill, Farrow claimed that an array of officials, from the White House to the Congressional Research Service to the Justice Department, have said making Puerto Rico somewhat autonomous would be unconstitutional.

“Self-determination is not you come up with whatever issues you want, and the United States has to accept it,” he said.

Modified commonwealth status also would create policy nightmares for the United States, Fuentes said.

“If you give this to Puerto Rico, every state is going to want it, and there will be no union,” he said.

One reason behind wanting to maintain a commonwealth has to do with money, Farrow said. A slew of U.S. businesses operate factories and have offices on the island, where Puerto Rico’s unique status allows businesses to stay there tax-free, as if they operate on foreign soil.

But Velázquez maintained in a statement Wednesday that her bill is simply the best method of providing a way for Puerto Ricans to study their future — something islanders themselves need to be in charge of.

“The legislation I introduced gives the people of the island the right to decide,” she said. “Dialogue and consensus are the best methods to achieve a democratic, fair and transparent self-determination process for Puerto Rico.”

Through the Fortuño-Serrano bill, Puerto Ricans would first decide whether to maintain the status quo as an unincorporated territory. If islanders vote no, they would then decide to become a state or become independent.

“The U.S. Congress needs to provide a process,” Fuentes said.

The bill has some powerful bipartisan co-sponsors, including Majority Leader Steny Hoyer (D-Md.) and Minority Whip Roy Blunt (R-Mo.).

Fourteen witnesses are expected to testify at today’s hearing, an eclectic mix of academics, legal experts and Puerto Rican officials. The hearing is expected to be crowded, with supporters of the three main options weighing in.

A second subcommittee hearing has been scheduled for April 25 and is expected to be far more political: the presidents of the island’s political parties and leaders of the Puerto Rico Senate and House of Representatives are expected to testify.

Despite the stark differences between the bills, the timing of the hearings — early in a new Congressional session — is a good sign movement on Puerto Rico’s status could happen soon, Fuentes said, adding that the target date for a vote on the Puerto Rico issue is 2009.

“The U.S. Congress is finally realizing that they have to deal with this issue,” Fuentes said.

One issue that might effect the course of the Puerto Rico debate involves another non-state with Congressional representation issues — the District of Columbia.

If the courts eventually decide that Congress can grant D.C. a full House vote under the Constitution’s District clause, Puerto Rico might have a similar option under the Territory Clause.

“That would raise the issue in Puerto Rico — ‘Do we have another path?’” Farrow said.

If Puerto Rico were to ever become a state, it is unclear how the island would turn out politically, Fuentes said.

Residents are divided between statehood, independence and status quo advocates. Top leadership is split partywise: Acevedo Vilá is a Democrat and Fortuño is a Republican, but the man who is perhaps the island’s biggest statehood advocate — Senate President Kenneth McClintock — is officially a Democrat.

“You can’t tell,” Farrow said.