BY PABLO BACHELET

WASHINGTON - Supporters of statehood for Puerto Rico launched a campaign Monday to persuade the U.S. Congress to force a vote on the contentious issue -- but in a way that opponents say unfairly stacks the deck in statehood's favor.

Leaders from the pro-statehood New Progressive Party presented more than 100,000 signatures in favor of a binding referendum on the island's status -- an idea proposed in December by a White House task force.

The battle over status has been going on for more than four decades and divided the island's population. Those preferring the current commonwealth status have prevailed over statehood in three referendums, with the full independence option coming in a distant third.

Commonwealth gives islanders U.S. citizenship and other benefits and exempts them from paying U.S. federal taxes. But they can't vote in presidential or congressional elections and are subject to many U.S. regulations.

The presidential task force recommended a complex and binding plebiscite, perhaps involving two rounds of voting. Commonwealth advocates say the process would favor statehood proponents.

Luis Fortuño, Puerto Rico's nonvoting representative in Congress, said congressional supporters of the referendum idea planned to introduce a bill promoting the process.

''This has to be a bipartisan effort at the congressional level, and we will be pushing really hard to provide the U.S. citizens of Puerto Rico this unique opportunity to choose what our future should be,'' he said.

Puerto Rico Gov. Aníbal Acevedo Vilá and his ruling Popular Democratic Party favor an expanded commonwealth option.