The Boston Globe

Politics

US efforts to join ‘Law of the Sea’ treaty sinking as Republicans solidify opposition

WASHINGTON -- A three-decade effort to persuade the United States to ratify a global treaty ruling the high seas has again encountered rough waters, with three more Republican senators saying they would oppose ratification.

That brings the number opposed to 34 senators, enough to prevent ratification of the Law of the Sea treaty. The Constitution requires two-thirds Senate approval of any treaty.

Support for the treaty has been widespread, with leaders from the military, State Department, and business community contending it would help protect the country’s security and economic interests across the oceans. Ratification has been a top goal of Senator John F. Kerry, chairman of the Senate Foreign Relations Committee.

Opponents, however, say the treaty would undermine US sovereignty. Republican Senators Kelly Ayotte of New Hampshire and Rob Portman of Ohio announced on Monday they oppose ratification.

In a letter to Senate Majority Leader Harry Reid, a Democrat from Nevada, Ayotte and Portman said the treaty was not in nation’s best interests. “The terms of the treaty are not only expansive, but ill-defined,” the letter said.

A third Republican, Johnny Isakson of Georgia, had recently announced his opposition.

The United States is the only major power to not have signed the treaty, which was negotiated in 1982 and went into effect in 1994. Among other elements, the treaty established tribunals to adjudicate conflicts over territorial waters and other jurisdictional issues.

Supporters had included big business groups such as the oil and gas industry, which wants to protect US interests in the increasingly navigable regions of the Arctic. The telecommunications industry also supported US participation in the treaty, which could affect the laying of thousands of miles of underwater cables that transmit Internet traffic.

Kerry, who held several hearings on the treaty, has repeatedly said he would delay a vote until after the fall elections.

His spokeswoman, Jodi Seth, blamed Monday’s development on partisan politics. “It’s not news to anyone that right now we’re in the middle of a white-hot political campaign season where ideology is running in overdrive,” she said.

“No letter or whip count changes the fact that rock-ribbed Republican businesses and the military and every living Republican secretary of state say that this needs to happen, and that’s why it’s a matter of ‘when’ not ‘if’ for the Law of the Sea.”

Bobby Caina Calvan can be reached at bobby.calvan@globe.com. Follow him on twitter @GlobeCalvan.