The leaders of Puerto Rico's three political parties came to Washington yesterday to renew their appeal for a referendum that would allow voters on the Caribbean island to decide whether it should be an independent republic, the 51st state or continue its status as a U.S. commonwealth.

But their testimony before the Senate Energy and Natural Resources Committee proved so quarrelsome that Chairman J. Bennett Johnston (D-La.), chief sponsor of the legislation, concluded a four-hour hearing by making all three take a public pledge to support his bill.

"We can do it this year," Johnston said, sounding like a football coach attempting to inspire his players. The party leaders remained skeptical that Johnston will be able to push the measure through Congress in time for balloting late this year.

The House Republican leadership has failed to endorse the issue this year, although it had been repeatedly endorsed by President Bush. Without the leadership's support, Resident Commissioner Jaime B. Fuster (D-P.R.), the island's non-voting member of the House, has warned that the measure's prospects are dim.

While Johnston was enthusiastic about his measure yesterday, the hearing may have added to concerns about the fate of his bill. Two senior Republicans on the panel, Sens. Malcolm Wallop (Wyo.) and Don Nickles (Okla.), voiced serious reservations about the measure.

"What I see are differences -- differences in culture, differences in language," said Nickles, questioning whether Puerto Rico should be offered the possibility of statehood. The island's political leaders had agreed that Puerto Rico, where only 1 in 5 residents is fluent in English, should not surrender either its Hispanic culture or its Spanish language to become a state.

Wallop, the ranking Republican on the panel, cited fears of an impasse with the House over the legislation. Last year, an impasse in the Senate killed a bill the House had passed without dissent, and the same problem is considered possible this year.

Wallop also questioned why Puerto Rico's legislature did not simply authorize the referendum on its own. The political leaders responded that without Congress's sanction, such a vote would be meaningless.

The Puerto Rican party leaders sharply attacked each other's proposals, and one sniped at the Spanish of Sen. Pete V. Domenici (R-N.M.), saying it was so poor it smacked of "Tonto and the Lone Ranger."

Ruben Berrios-Martinez, president of the Puerto Rico Independence Party, also mocked Domenici's assurance that some of his state's early Spanish culture was intact decades after statehood. "You won't stand a chance of being elected a municipal assemblyman in Puerto Rico with that attitude," Berrios-Martinez told Domenici.

Former governor Carlos Romero Barcelo, leader of the statehood party, complained that Johnston had "lopsidedly tilted" his bill for the commonwealth option by capping some welfare benefits residents would receive if Puerto Rico joins the Union. Romero Barcelo insisted that was "unconstitutional," but both Johnston and Wallop disagreed.

The question of how much, if anything, statehood would cost the federal government proved to be a key issue. Johnston warned Romero Barcelo that the Senate Finance Committee had trimmed the benefits to be accorded under statehood in order to make its benefits comparable to those to be granted under a continuation of the island's commonwealth status. Any bill that would add large costs to the federal government would have little chance of passage, Johnston said.

Both Berrios-Martinez and Gov. Rafael Hernandez Colon, leader of the commonwealth party, attacked the increased federal welfare benefits statehood supporters have said they could bring the island's poor. "The battle cry of many Puerto Rican statehooders, 'Statehood for the poor,' is a far cry from 'Give me liberty or give me death,' " Berrios-Martinez said.