The international community is growing increasingly impatient for the Senate to ratify a key nonproliferation pact amid warnings that a global taboo against nuclear weapons testing may falter if momentum toward the accord’s entry into force is not seen in the next half-decade or so.

The Comprehensive Test Ban Treaty, which would make it illegal to detonate a nuclear device, was opened for signature 20 years ago but has yet to become international law in large part because the United States has not ratified the accord.

Lassina Zerbo, executive secretary of the Comprehensive Nuclear-Test-Ban Treaty Organization, the Vienna-based U.N. organization charged with overseeing implementation of the treaty, said he fears if another five or eight years passes without U.S. ratification, international support for the accord could weaken, particularly if no other nuclear weapons states such as Pakistan or India ratify the accord in the interim.

“We get into the risk to lose what we’ve achieved for 20 years,” Zerbo said in an interview.

But don’t expect the Senate Foreign Relations Committee to begin consideration of the treaty anytime soon.

Chairman Bob Corker of Tennessee told CQ Roll Call last week that “there’s been no discussion” on holding a committee vote on the nuclear accord.

Secretary of State John Kerry attracted some media attention last October when he declared “I am determined that in the months to come, we’re going to reopen and re-energize the conversation about the treaty on Capitol Hill and throughout our nation.”

However, in the more than three months since Kerry made those remarks at an Energy Department nuclear stockpile stewardship event, there has been no evidence of a concerted administration campaign to lobby senators in favor of the treaty.

Early on in his administration, President Barack Obama promised to seek Senate approval of CTBT but decided to focus first on negotiating and achieving Senate ratification of what became the New START treaty with Russia, an accord that replaced an older strategic arms control pact that expired at the end of 2009. But negotiating the treaty with Moscow and then pushing it through the Senate proved to be much more time-intensive and politically costly than the administration had initially anticipated.

Coupled with the gradual winnowing of Republican foreign policy moderates in the Senate such as Richard G. Lugar of Indiana through electoral defeats and retirement, the Obama administration essentially determined after the New START ratification fight it did not have the votes or the energy for another uphill arms control treaty push.

“I think it was nearly ripe [to ratify CTBT] during the beginning of the Obama administration but the priority was on the New START treaty, which I respect,” said Zerbo, a diplomat from Burkina Faso, who previously served as head of the CTBTO’s International Data Center. “There was a lot more energy and resources put into [New] START than anyone had expected when they started the negotiations and that didn’t help the CTBT.”

Bill Clinton was the last president who tried to secure ratification of CTBT but his effort fell far short of the minimum two-thirds vote needed in the Senate.

Opponents of U.S. ratification contend there may come a day where it will be necessary for the United States to return to underground testing in order to ensure a reliable nuclear deterrent, particularly as it builds and deploys new combinations of older warhead components. It’s additionally argued that many of the U.S. weapons scientists who gained expertise through years of testing are in the process of retiring and the generation taking their place lacks some of their hands-on experience, potentially raising questions about their ability to guarantee the reliability of the U.S. nuclear arsenal.

The United States has observed a moratorium on nuclear testing since 1992.

A Global Stalemate

For the test ban treaty to “enter into force” and become law, eight advanced nuclear countries must ratify the accord. Those countries are China, Egypt, India, Iran, Israel, North Korea, Pakistan and the United States.

Siddharth Varadarajan, an Indian journalist and editor of The Wire, sees a global deadlock for at least four of those countries — Pakistan, India, China and the United States — so long as Washington does not ratify.

“Pakistan will not sign and ratify the CTBT as the smallest and weakest of the nuclear-armed states before India does, India will not do the same until China does and the Chinese will not do it until the U.S. does,” said Varadarajan, speaking last week on a panel at a Vienna conference commemorating the 20th anniversary of the treaty being opened for signing.

Varadarajan argued it was up to the United States to take the initiative in ratifying the treaty as it has by far the superior nuclear arsenal.

“In technological terms, the treaty as it stands places the U.S. at a huge advantage in terms of its ability to continue to design weapons,” he said. “It has the greatest amount of scientific, technical, historical knowledge that it can build upon to ensure that it has far more destructive weapons than any other potential nuclear rival. Despite that, the U.S. wants to keep its option open to test, which is astonishing.”

Daryl Kimball, executive director of the Arms Control Association, said absent Senate approval of the treaty in the short-term, there are other steps the United States can take to reinforce international support for the nuclear pact.

He suggested that in the wake of North Korea’s January nuclear test, the U.N. Security Council should pass a new resolution calling on all nations to refrain from nuclear testing. Additionally, now that the Iran nuclear deal has been implemented, there is a new opening for Iran to be coaxed into ratifying the treaty in concert with fellow Middle East holdouts Egypt and Israel.

“We need to think about other measures to reinforce the global taboo against testing so that it doesn’t erode,” Kimball said. “We have to think about other ways to reinforce the moratorium