Last December, 25 Americans, along with counterparts from Canada, Germany, France, Romania, and the United Kingdom, joined Ukrainians on an urgent mission to help them defend their nation.

A few days earlier, several Ukrainian ships and their crews had been seized on the Sea of Azov. In response, Ukraine had asked America and its allies to conduct an extraordinary joint overflight to produce certified photographic evidence of what was really happening.

In an era of deep fakes and precision-guided disinformation, ready access to unquestioned facts gives America and its friends an instant strategic advantage.

But more than that, America’s friend was calling for help, and only America could be counted on to lead the response. Pulling together such an extraordinary, short-notice, multi-nation surveillance mission was only possible because the United States and its allies already had a long-standing agreement that almost no one has heard of: the Open Skies Treaty, which established a regime of observation overflights over the territories of all member states. The United States, Russia, and 32 other Euro-Atlantic countries—most of whom are U.S. allies—have been quietly using this treaty for years to help make sure that the very real tensions that trouble the region at least stay focused on facts, not fakes.

Rumors are now swirling about President Donald Trump deciding to withdraw the United States from this treaty. Congress, our allies, and the public have been kept in the dark. To make matters worse, there is no evidence that the Trump administration has considered how walking out on the treaty would impact our national interests. There has not been any real discussion about how abandoning our commitment to Open Skies would undercut Ukraine, or more broadly affect the security of our European allies, who rely on the tools of the treaty to gain independent insight into the military might of their neighbors, including Russia.

Maybe we should not be too surprised. Trump seems to have little regard for the security interests of most of America’s friends, or for the legacies he inherited from other people’s hard work. In today’s hyper-partisan political climate, one might guess that a move against the Open Skies Treaty is just one more score to settle with President Barack Obama. But this time, the inheritance President Trump is thinking of gambling away was handed down by fellow Republicans.

Open Skies’ Origins

Back in early 1989, then-President George Herbert Walker Bush put a steely eyed challenge to the Soviets still running Russia: let America and its allies take a look around at Russia and its Eastern bloc partners with periodic unarmed surveillance flights, and we’ll let you do the same. The imagery collected would build confidence by letting each side distinguish trucks from tanks. Each side could effectively take a plane apart to make sure everything was on the level. The inspected party could even have their own military personnel onboard the flights.

The United States and its allies had no plans or interest in attacking Russia and were willing to prove it. After so many decades of fearing military sneak-attacks and nuclear escalation, letting everyone collect and share some basic facts would allow all the countries across the Euro-Atlantic region to breathe a little easier.

President Bush had lifted the mutual overflight idea from another Republican president, Dwight D. Eisenhower. Both presidents understood all too well that building up military capacities in response to faulty assumptions about an adversary was not only wasteful, it was dangerous. Both men had fought in and survived a world war. They understood how much damage modern conventional bombs, tanks, and machine guns could do to the world that Americans are trying to build. They knew how miscalculations and misunderstandings could spark national disaster in any age. They wisely saw that in the nuclear age, such risks are intolerable.

That is why the late President Bush worked so hard at the Cold War’s end to use America’s rising dominance and improved relationship with Russia to forge lasting unilateral, bilateral, and multilateral moves that significantly cut the numbers of weapons of war and greatly lowered major power tensions.

Trump’s Security Inheritance

Fast forward a quarter of a century. We know now that those deals helped lock in years of unprecedented stability and predictability for America’s European allies—and by extension, for America itself. Yes, tensions and dangers have flared again in recent years—but how much worse would matters be today without all the institution-building that Bush and the other post-Cold War presidents had done?

No treaty or agreement is ever perfect, but President Trump was very lucky to inherit a whole set of institutions and relationships to help him manage threats and hold together America’s Euro-Atlantic alliance.

One might think he, of all people, would recognize his good fortune at inheriting substantial assets of power and influence from those who labored before him. We cannot help but observe that, before he arrived at the White House, President Trump would reportedly draw upon his inherited wealth to bail himself out when his financial gamble proved to be too reckless. He is now applying that same approach to this country’s foreign policy. The problem is, if a president gambles away all the treaties, alliances, and good will that he inherited, nobody will be there to bail the American people out.

Our understanding is that the initial drive to consider walking away from the Open Skies Treaty came while former National Security Adviser John Bolton was still on the job. For Bolton, it was never a matter of whether to walk away from what he viewed as America’s entangling treaties, it has always a matter of when he could make it happen.

Throughout his career, Bolton has pushed policies that—just like Trump once did on New Jersey casinos and the United States Football League—riskily leveraged hard-earned gains in arms control, alliance relationships, and great power strategic stability in pursuit of supposedly grander payoffs for American power and security. During his previous stints in government, Bolton had to navigate around other Republican national security leaders, including presidents, who were usually reluctant to make reckless bets with the large security dividends the United States earns from standing atop a mildly binding system of rules, habits, and alliances.

This time around, though, Bolton answered only to one.

Bolton’s influence was palpable in President Trump’s short-sighted abandonment of the Iran nuclear deal. Bolton’s hand could be seen in Trump’s abrupt move to scrap, rather than fix, Ronald Reagan’s Intermediate-range Nuclear Forces Treaty. Walking out of the Open Skies Treaty would simply squander one more inherited asset that has paid solid, steady returns for American national security.

America’s European allies, Congress, and the American public must reject this reckless move. If this President continues to fritter away the structures of openness, confidence, and Trans-Atlantic cooperation that Republicans like Dwight Eisenhower and George H.W. Bush helped build and bequeath, our diplomatic standing – and our very security – may never recover.

“A retreat from American leadership, from American involvement,” the late President Bush warned in his 1993 farewell remarks at Texas A&M University, “would be a mistake for which future generations, indeed our own children, would pay dearly.”

It has been almost a year since the passing of the president who helped to build a safer, more secure world. The Open Skies Treaty is part of that legacy. We cannot let our current President squander it.