In the last several years, a number of troubling events have revealed weaknesses in Russian nuclear security. A Russian general in command of nuclear weapon storage sites was fired due to massive corruption. A colonel in the Russian Ministry of Interior in charge of nuclear security inspections was arrested for soliciting bribes to overlook security violations. One American researcher visiting a nuclear facility was told it would take merely $100 to bribe his way in.

Graft in Russia is rife, and corruption plus available uranium is a troubling combination. This vulnerability is heightened by the fact that at many nuclear sites the accounting systems to track uranium and plutonium could not sufficiently identify thefts of newly manufactured or older stored fissile materials. More broadly, Russia does not possess a master baseline inventory of all nuclear materials produced in the former Soviet Union — and where all of it is today.

At a 2010 summit of world leaders, President Barack Obama described nuclear terrorism as “the single biggest threat to U.S. security.” He’s right — but as the crisis in Ukraine festers, recent U.S. actions have unraveled decades of successful cooperation with Russia to reduce the risk.

While some argue that the United States needs to “punish” Russia due to Moscow’s contribution to the crisis in Ukraine, this is akin to cutting off our nose to spite our face. Given the threat from “loose nukes” to our national security, the United States should take steps to jump-start U.S.-Russian nuclear security cooperation.

When the Soviet Union collapsed in 1991, American policymakers suddenly faced a frightening new threat: Poverty and chaos caused a complete breakdown in security throughout the former Soviet nuclear complex. Insiders at top-secret Russian nuclear weapons plants tried to steal and sell nuclear materials on the black market. Unpaid guards at nuclear sites left their posts to search for food. A senior White House science adviser even discovered more than 150 pounds of highly enriched uranium — enough for several nuclear bombs — sitting unguarded in lockers in the middle of Moscow.

In response to this threat, the United States spent billions of dollars under the Cooperative Threat Reduction (CTR) program to help Russia secure its nuclear materials and facilities. From the deactivation of almost 8,000 Russian nuclear warheads to the building of a massive storage facility for 27 tons of fissile materials, CTR was arguably the most successful American foreign aid program in history.

Following the conclusion of the CTR program in 2013, the U.S. Department of Energy (DOE) and Russia’s state-owned nuclear company Rosatom signed a comprehensive nuclear cooperation agreement. This agreement, which was designed to build trust between the two countries, called for projects ranging from the development of advanced nuclear security and safety technologies, to visits by each side’s scientists to the other’s most sensitive nuclear labs and facilities.

Less than seven months after the agreement was signed, however, the DOE dealt a devastating blow to Russian-American nuclear security cooperation, banning Russian nuclear scientists from visiting the United States while also banning DOE nuclear scientists from visiting Russia.

The current defense budget, passed seven months after the DOE’s action, also bars all funding for nuclear nonproliferation activities and assistance in Russia.

Its pride wounded, Russia retaliated, first announcing it would boycott the 2016 nuclear security summit in Chicago and then informing U.S. officials it would no longer accept American aid to help secure Russia’s weapons-grade uranium and plutonium — a significant blow to U.S. national security.

Nuclear security in Russia is undoubtedly better than it was in the 1990s. Guards at nuclear sites are paid on time. Perimeter fences surrounding these sites no longer have holes. Fissile materials are no longer stored in lockers. That’s the good news.

The bad news is that while physical security at nuclear sites is greatly improved, real problems still remain. Russia continues to have the world’s largest nuclear stockpile and there are more than 200 buildings and bunkers where highly enriched uranium or separated plutonium is stored. Sophisticated criminals could still exploit the remaining weaknesses in Russian nuclear security.

We know that Osama bin Laden considered a nuclear attack targeting American civilians to be a legitimate action, and last year Islamic State stole 88 pounds of non-enriched uranium compounds from a university in Mosul. With nearly 2,000 Russian citizens fighting with Middle East extremist groups, if fissile material does end up in the hands of militants, it is quite possible it will have originated from Russia.

The DOE should work with Rosatom to restart the September 2013 agreement and implement the reciprocal nuclear site visits, scientist-to-scientist cooperation and joint-research the agreement envisions. The personal relationships developed over decades of cooperation between Russian and American scientists are too important to jeopardize — we are only shooting ourselves in the foot by cutting these off.

The United States should also understand that the narrative from the 1990s whereby the United States is a donor and Russia is an aid recipient is no longer acceptable in Moscow. Going forward, nuclear cooperation must be reframed as a partnership of equals, with both sides contributing to the conversation about how and why to strengthen security. Republicans and Democrats should put aside partisan differences and fully fund U.S.-Russian nuclear security cooperation — whatever that ultimately involves. The Obama administration is proposing to spend $348 billion upgrading the U.S. nuclear arsenal over the next ten years. It’s worth spending a tiny fraction of that money to prevent loose nukes.

All of these steps require that the United States end the linkage between nuclear security cooperation with Russia and the crisis in Ukraine. While the current political environment makes this difficult, not doing so is foolhardy.