Business groups pushing the Law of the Sea Treaty saw their GOP allies sink ratification this week, losing yet another policy battle to conservative activists.

Lobbyists from the U.S. Chamber of Commerce and the National Association of Manufacturers had what in any other year would have been the key ingredients for passage — a hefty list of supporters on both sides of the aisle and a cadre of outside players, including odd bedfellows such as the American Petroleum Institute and environmental groups.

But months of aggressive lobbying — including personal appeals to Senate Foreign Relations Chairman John Kerry (D-Mass.) from chamber President and CEO Tom Donohue — could not counter political imperatives for Republican Sens. Kelly Ayotte (N.H.) and Rob Portman (Ohio), two Romney surrogates said to be on his vice presidential shortlist. Earlier this week, the two Senators along with GOP Sens. Mike Johanns (Neb.) and Johnny Isakson (Ga.) added their names to the list of lawmakers publicly opposing the 30-year-old agreement, pushing the total to 34 — the exact number opponents needed to sink the treaty on the Senate floor. Treaties need an affirmative two-thirds majority for ratification.

Since January, business groups, the oil and gas industry — another traditionally Republican interest — and wireless carriers Verizon and AT&T had pushed for the treaty, in hopes of protecting newly accessible territories ripe for deep-sea exploration and providing guidance for laying thousands of miles of underwater cables that transmit Internet traffic.

The American Petroleum Institute collaborated with the chamber and NAM to run advertisements in Roll Call, The Hill, the Wall Street Journal and the Washington Times on June 28, the day all three groups testified in favor of the treaty.

But, a week later, chamber lobbyists seemed to have thrown up their hands, telling Roll Call the political climate wasn’t ripe. Kerry said he wasn’t going to mark up the treaty until after the elections because of the tense political climate.

At the same time, conservative opponents, led by Heritage Action for America, the issue advocacy arm of the conservative think tank the Heritage Foundation, made vigorous and repeated appeals at gatherings throughout conservative Washington, including the weekly meetings run by anti-tax lobbyist Grover Norquist and the Republican Study Committee, according to a source present at both meetings.

This is the latest in a series of chamber-backed measures — including legislation to raise the debt limit, reauthorize highway programs and renew the charter of the U.S. Export-Import Bank — that have run contrary to conservative wishes.

A parallel phenomenon has played out on Capitol Hill since the debt ceiling debacle last summer broke the tensions between conservative Republicans and their more moderate leaders wide open.

Historically, conservatives have a natural distrust of the United Nations, but Democrats were hopeful that industry support would tip the scales in favor of the U.N.-brokered treaty.

The development was a blow to the Obama administration and Pentagon officials, who had argued the treaty would improve national security and enhance U.S. standing in the world. The treaty was concluded in 1982 and has been in force since 1994. The United States is the only major nation that has refused to sign the pact.

Presumptive GOP presidential nominee Mitt Romney has yet to comment publicly on the issue this election cycle, but in 2007, a spokesman for his 2008 campaign said that he, like the other Republicans vying for the party’s nomination that year, opposed the treaty.

Some have suggested that Portman and Ayotte came out against the treaty because of their relationship with the Romney campaign. In election years, Congressional Republicans and Democrats typically try to work together to minimize any differences with their respective presidential candidates and play up areas of agreement, aides said.

“The Romney campaign indicated that they were opposed to the treaty but didn’t want to get off message from the economy, so they went through back channels,” said one conservative strategist opposed to the treaty.

A Romney campaign spokesman adamantly denied a role in the developments, saying, “That is false and completely ridiculous.”

Both Ayotte and Portman said they made their decisions independently and have not been in touch with the Romney campaign on the issue.

“Rob announced his opposition after weeks of careful consideration of the treaty and hearing from advocates on both sides of the debate,” a Portman aide said, adding that, to his knowledge, there has been no contact with the Romney campaign on the issue.

Ayotte said that neither Heritage Action nor the Romney campaign played a role in her thinking on the treaty.

“I actually read the Law of the Sea Treaty myself to draw my own conclusion,” Ayotte said. “They do some excellent work at the Heritage Foundation, but I draw my own conclusions.”

Lobbyists at the chamber, the API and NAM dismissed the developments as a minor setback.

“Obviously I never intended to have a vote until after the election because I wanted this issue removed from the political season, but I also made that decision mindful of the fact that I wanted those businesses and the military to have time to work the Hill and make their case up here,” Kerry said in a statement to Roll Call. “It’s breathing space. I think when many senators learn more about this treaty and its supporters, they’re going to be persuaded.”

Dan Holler, a spokesman for Heritage Action, was cautiously optimistic that his side had it in the bag.

“We assume that bad policies never die completely,” he said.