Amid the controversy over President Donald Trump's declaration of a national emergency at the Mexico border, a small cadre of Yale Law students has been key in arming a bipartisan group of national security heavyweights to oppose the move.

Sixty former national security officials, including former Secretaries of State Madeleine Albright and John Kerry and former Defense Secretary Chuck Hagel, this week released joint declaration laying out their myriad arguments against Trump's emergency declaration in hopes of swaying lawmakers to oppose it.

Behind the scenes, a half-dozen students in Yale Law School's Rule of Law Clinic worked for weeks to research the matter and help draft the joint declaration, which in addition to being placed in the Congressional Record will be filed as part of the court record in the lawsuits challenging the emergency declaration.

The declaration was released the day before the U.S. House of Representatives voted to block Trump's declaration of a national emergency at the border with Mexico—a move that is largely intended to bolster lawsuits challenging the declaration, given that the president is likely to veto any bill that might emerge from the Senate.

Others among the signatories of the joint statement are former CIA Director John Brennan, former Defense Secretary Leon Panetta, former Homeland Security Secretary Janet Napolitano and former United Nations Representatives Susan Rice and Samantha Power.

“We have lived and worked through national emergencies, and we support the President's power to mobilize the Executive Branch to respond quickly in genuine national emergencies,” the joint declaration reads. “But under no plausible assessment of the evidence is there a national emergency today that entitles the President to tap into funds appropriated for other purposes to build a wall at the southern border.”

Second-year law student Danielle Zucker said she and five other classmates from the clinic—their group adopted the nickname Blue Steel—waded through hundreds of emails as they helped shepherd the draft through multiple revisions, wrote footnotes and conducted research. They began working on the project weeks before Trump actually declared a national emergency on Feb. 15.

“It's exciting to take an issue that's something I care about and is something all the people who signed on care deeply about—and to feel like you are a part of a group that's having an effect on the national conversation,” Zucker said in an interview Tuesday, shortly before the House vote. “All the students working on it were pretty motivated to put in the time and get this right.”

The joint declaration was an outgrowth of an earlier policy statement that the Rule of Law Clinic helped 10 former national security officials release in opposition to Trump's travel ban. Those 10 original signatories helped circulate the new document highlighting problems with the border emergency declaration among an even wider group of national security colleagues. They sought out experts in counterterrorism, human trafficking, relations with Mexico and other areas that touch the border emergency debate, said clinic instructor and former Yale Law Dean Harold Koh.

“Somebody has to make an assessment that there is an emergency,” Koh said. “Trump is asserting no facts and putting forth no experts. And here are people who dealt with national emergencies their whole lives and are in fact are deferential to the claim when there is any basis to assert it.”

“The people on this list were responsible for protecting the country and did so through numerous crises through numerous presidents, Democratic and Republican alike,” Koh continued. “They ought to know the different between an emergency and a non-emergency.”