This year, violent extremists linked to the Islamic State spied on the home and office of a person involved with storing large quantities of dangerous nuclear material. The motive for the surveillance is unknown, but authorities speculate that the group might want the material to use in an attack.

The country where this surveillance happened? Belgium, in the months before the deadly March 2016 bombings. Thankfully, no nuclear material was involved in those attacks.

In the popular imagination, nuclear threats come in the form of bombs exchanged by nuclear weapons states. Intelligence agencies and national security experts are much more focused on the threat of a few pounds of nuclear material falling into the hands of a violent, non-state group like ISIS.

U.S. funding for the programs to secure and destroy unsecured nuclear stockpiles has declined in recent years.

The U.S. has effective programs to secure and destroy unsecured stockpiles around the world. First championed by former Sens. Sam Nunn (GA) and Richard Lugar (IN), these nonproliferation efforts have led the U.S. to become the world’s leading expert on secure disposal of surplus uranium.

The world has no shortage of this material: It can be found in Africa, Asia, and Europe; in unsecured research reactors; 1960s-era electricity-generating plants; and the engines of decommissioned Russian nuclear submarines. But U.S. funding for the programs to deal with it has declined in recent years.

Why would U.S. nonproliferation programs stagnate, given the danger and need?

Deteriorating relations between the U.S. and Russia are partly to blame. It’s become more difficult for U.S. nonproliferation experts to work in the country that contains much of the world’s loose nuclear material.

The Pentagon’s nuclear modernization plans are also behind declining nonproliferation budgets, however. As military leaders and contractors look for funding sources to improve U.S. nuclear weapons, nonproliferation funding seems like an easy pot to pilfer.

Now, more than ever, the U.S. needs to invest in nonproliferation.

FCNL has worked with the Obama administration and Congress to increase funding for these programs. This year, our goal is to increase nonproliferation funding beyond the president’s budget request. We have had some success: In the Senate’s Energy and Water Appropriations bill, nonproliferation programs received $20 million over the president’s request. The parallel House bill hasn’t yet been approved, but in committee representatives added nearly $120 million in nonproliferation funding above the president’s request.

These funds go to support critical programs. They support research and development for more effective radiation detection systems at shipping docks, airports, and other high-risk areas; and efforts to secure vulnerable sites where radiological and nuclear materials are present.

Rather than spending our tax dollars to build new nuclear weapons, the U.S. government should devote even more money to the tasks of securing and ultimately destroying unsecured stockpiles of existing nuclear weapons and materials. Groups like ISIS operate by creating as much damage, destruction, and terror as they can. A nuclear attack would serve their purposes well. The U.S. needs to maintain and strengthen its commitment to and investment in preventing the next attack in Belgium, Turkey, Nigeria, or the U.S. from being a nuclear one.