Ninety-two years after the United States received Puerto Rico as one of the spoils of the Spanish-American War, members of Congress will try again this week to decide what to do with the impoverished Caribbean island.

Congressional leaders have agreed with President Bush that a plebiscite next summer should decide the political status of Puerto Rico, which is now a "commonwealth" nation with tailor-made privileges and restrictions. But the House and Senate have embarked on sharply different routes to that election. Many officials doubt the differences will be resolved this summer.

"The bigger issue is time," one congressional aide familiar with the issue said last week. "If it doesn't happen in July, there isn't going to be any plebiscite."

Chances of the issue being resolved quickly suffered a setback two weeks ago when the Virgin Islands' non-voting delegate, Ron de Lugo (D), the House member managing the issue, came down with pneumonia and a collapsed lung. He is not expected to attend a subcommittee hearing in New York Monday that he was supposed to chair.

Aides said de Lugo, 59, is determined to return to Capitol Hill by Thursday to preside over a second hearing by his Interior subcommittee on insular and international affairs. But even if he does, aides concede the House will have to move quickly to catch up to the Senate.

As important as the timetable may be the fact the House and Senate have decided on markedly different methods for Puerto Rico to achieve statehood, independence or an enhanced status as an American "commonwealth" that would offer increased self-government and federal benefits. Those are the three options that all sides have agreed to place before the island's voters.

The Senate has chosen a one-step process, drafting a detailed plan that would become self-executing after the voters speak. The House has decided for a two-step process that would give Congress a second chance to review the issue and spell out details of whatever option the voters select.

Former Puerto Rican governor Carlos Romero Barcelo, a leader of the statehood forces, was in Washington last week to lobby Congress and said the House leadership had assured him the legislation was on a "fast track."

Jose Roberto Martinez, director of Puerto Rico's Federal Affairs Administration and a proponent of enhanced commonwealth status, said in an interview that the issue needs to come before a House-Senate conference committee by August or September if differences in the two versions are to be resolved this year.

The Senate's version cleared the Energy and Natural Resources Committee last August amid charges it was tilted in favor of statehood, the option President Bush has endorsed. The bill was referred to the Finance Committee, where aides say senators are likely to redraw some of the measure's financial provisions Tuesday morning in an effort to answer complaints that the bill favors statehood.

At stake during the committee markup are billions of dollars in financial aid and tax benefits. In an effort to strengthen the island's economy -- about 60 percent of its 3.4 million residents are below federal poverty limits -- Congress made the island into a huge tax shelter: Neither residents nor corporations there pay federal income taxes.

Residents are U.S. citizens but cannot vote in U.S. elections. They are eligible for some federal welfare programs, but most benefits are capped well below levels paid on the mainland. Since the Constitution requires uniform taxes among the states, the Puerto Rican advantage would have to be erased under statehood.

Just how the tax exemption should be phased out and benefits added are among the top issues that the Finance Committee will address.

Until last year, advocates of commonwealth status typically led most polls on the island. After the Senate Energy Committee approved a bill to allow an immediate increase in welfare benefits after statehood, the statehood forces surged ahead in polls, prompting charges that the panel had "front-loaded" the bill in favor of statehood.

Until last week the issue received little partisan attention. Senate Majority Leader George J. Mitchell (D-Maine) charged Wednesday in a floor speech that the White House was interfering with the effort to set up a neutral election.

Mitchell cited the appearance of two senior White House aides, Andrew Card and Chase Untermeyer, at statehood and Republican rallies on the island, where they predicted Puerto Rico would send Republicans to Congress. Mitchell said that proves the White House "is openly campaigning in an effort to manipulate the result for partisan advantage."

Deputy White House press secretary Stephen T. Hart rejected Mitchell's complaint. "We have a position and we're advocating that position," he said. "We're not interfering in the process in any way."

Some advocates of statehood for the District of Columbia have said they want to piggyback their proposal onto the Puerto Rican proposal, an idea that has found little support in Congress. Statehood advocate Romero Barcelo said the District's unique status under the Constitution means it should fight its battle alone.