A little past midnight at a gas station in Mexico a man approached a car, forced the driver and passenger out at gunpoint and bound them in an empty parking lot before driving off. In the carjacked vehicle was Cobalt-60, a highly radioactive material that could be used to make a dirty bomb. The radioactive cargo disappeared for two days before eventually being recovered.

The Mexico incident, which took place in December, is part of a troubling pattern of loss and theft of weapons-usable materials worldwide. The International Atomic Energy Agency reports that more than a hundred thefts and other incidents involving nuclear and radioactive material occur every year. Fortunately, there was some real progress made in preventing nuclear terrorism when President Barack Obama and more than 50 world leaders gathered for the Nuclear Security Summit in The Hague in late March. Now, Congress must rise to the challenge and do its part.

Around the world the global stockpile of nuclear materials is large enough to build 80,000 weapons like the one that destroyed Nagasaki. It doesn’t take much to do damage: A grapefruit-sized amount of plutonium or enough weapons-grade uranium to fit into a 5-pound bag of sugar can be fashioned into a weapon. Terrorist groups from Afghanistan to the North Caucasus to Japan have sought to acquire nuclear materials over the past two decades.

To his great credit, Obama has recognized the problem and initiated a series of summits to address it. Real progress here has been made during his presidency. Highly enriched uranium has been cleaned out from 12 countries since 2009. Dozens of countries have updated their nuclear security laws and regulations. Many more nations are taking necessary steps to support common sense policy initiatives, like two anti-nuclear terror treaties. The summit in March saw a big step forward with a new initiative on securing radioactive materials that could be used in a dirty bomb.

But bolder action and dedicated U.S. leadership in both the White House and Congress is needed to address the roots of security challenges that still remain. Most problematically, there are no globally agreed-upon standards for securing weapons-usable nuclear material. Instead countries are left to their own devices and varying levels of initiative. Like a chain restaurant without a health code, this creates a self-policing scenario where quality and care varies and health risks abound. A legally binding agreement that defines effective standards and closes existing gaps would be a major step forward.

Closer to home, Congress should support several key nonproliferation initiatives. Critically, Congress should promptly approve the 2005 Amendment to the Convention on the Physical Protection of Nuclear Materials and the International Convention for the Suppression of Acts of Nuclear Terrorism. These treaties expand legal protections against the loss or theft of these dangerous materials and their approval would be a notable step forward in efforts to guard against an act of nuclear terrorism.

Another focus on Capitol Hill should be fully funding the Global Threat Reduction Initiative, which was cut by 30 percent in the president’s budget released this month. Pound for pound, no program has done more to prevent nuclear terrorism. In March 2012, the program secured highly enriched uranium from Ukraine, ensuring that state was free of all weapons-usable nuclear material well before the recent turmoil. Just months before the December carjacking in Mexico, the program successfully recovered Colbalt-60 in Ciudad Juarez, returning it to the United States for safekeeping.

With each dollar cut in this and other nonproliferation programs, America is retreating, not leading the effort to prevent nuclear terror. Congress should restore funding to this and other nonproliferation programs that have fallen under the shortsighted axe of budget cuts.

Preventing one of the major threats of our time currently relies on a voluntary mishmash of security arrangements — we can and should do much better. Bolder action is needed to strengthen the persistent weak links in the chain to prevent the world’s most dangerous materials from falling into the wrong hands. Congress must now rise to the challenge. There is much work to be done.

Alexandra Toma is executive director of the Peace and Security Funders Group and founder of the Fissile Materials Working Group, a coalition of more than 70 bipartisan non-governmental organizations. Major General George A. Buskirk served in the National Guard from 1978-2004 and is adjunct general for the Indiana Army and Air National Guard.