WASHINGTON — In a surprise move, US Secretary of State John Kerry today announced a new push to get the Senate to ratify the Comprehensive Nuclear-Test-Ban Treaty.

Speaking at an event organized by the National Nuclear Security Administration, Kerry pledged to spend his last year in office making the case for why the US should sign onto the agreement, known as the CTBT.

"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," Kerry said. "Because there should be no doubt that it is in the best interests of our country to join the treaty and to urge others not to wait, but to go ahead and do so themselves as soon as possible."

Entry into the CTBT would legally prohibit the US from performing nuclear explosive tests – something the government has been doing on a de facto basis since 1992.

183 total states have signed the treaty, but only 164 have ratified it. More importantly, out of the 44 nations designated as "nuclear-capable states," India, Pakistan and North Korea have refused to sign the agreement, and only 36 have voted to ratify the agreement.

For the agreement to go into force, the eight remaining nuclear-capable states – China, Egypt, India, Iran, Israel, North Korea, Pakistan and the United States -- must ratify the document.

The last major push to ratify the CTBT came in 1999, when it failed in the Senate 51-48. But Kerry argued that the factors that led some to vote against it then – primarily concerns about the US ability to do non-explosive testing and the question of whether the capability exists to make sure others are not violating the treaty and, therefore, putting the US at a disadvantage –  are no longer concerns thanks to technological improvements.

"The factors that led some senators to oppose the treaty in 1999 have changed, and, so choices should change as well," Kerry said.

His comments came at a celebration honoring the 20th anniversary of President Bill Clinton's declaration that the US would move to a non-explosive testing regime, known as the Science-Based Stockpile Stewardship Program.

Unsurprisingly, the audience, largely made up of NNSA personnel connected to the non-explosive testing program, gave Kerry warm applause following his statements, which included a call to action for the scientists involved to educate those on the Hill about the realities of nuclear testing and verification in 2015.

He noted that the lack of information on the Senate is a "hurdle" when discussing nuclear information of all stripes, saying "we need to start having scientists come up and state the case."

"Approval of the CTBT is a fight that we can, and will, win," Kerry told the crowd. "I urge everyone to keep the faith. I know you'll keep [up] the fight."

The Secretary also touched on the Iran nuclear deal, which was officially adopted at the start of the week.

"This is for real, and it is really the start of the most far-reaching readjustment of a nuclear program since the dawn of the nuclear age," Kerry said of the agreement, which he helped broker.

While acknowledging the deal was "controversial" on the Hill, Kerry said he is optimistic about the situation.

"I believe they are going to comply," he said of Iran.

Twitter: @AaronMehta