But both men persisted. Despite the Cold War atmosphere, rampant mistrust, and fearmongering on both sides, the leaders engaged each other. Ultimately, multiple agreements were hammered out, including the Intermediate-Range Nuclear Forces (INF) Treaty and the START treaty. Over a four-year period, the former eliminated nearly 2,700 missiles.

Over the years, though, agreements with Russia to reduce nuclear arms have not followed a straight path of success. Shortly after the 9/11 attacks, George W. Bush announced his intention to withdraw from the Anti-Ballistic Missile (ABM) Treaty. Russian President Vladimir Putin responded by announcing that the INF Treaty might no longer be in Russia’s interests. Russia had ratified START II in 2000 but pulled out of the treaty after the U.S. withdrew from the ABM Treaty.

Most recently, New START took effect in 2011. In addition to placing a cap of 1,550 on deployed strategic nuclear warheads, a nearly three-quarter drop from START, New START also cut in half the allowable number of strategic nuclear-delivery vehicles, such as missile launchers and heavy bombers.

New START expires in 2021. If either side allows it to simply sunset, it will be the first time in several decades that a nuclear-arms-reduction treaty between the U.S. and Russia lapses.

As our hour was coming to an end, I asked Gorbachev whether he had any words of wisdom to improve our current dialogue. “Bring the conversation back to nuclear-arms reductions,” he said. “Encourage both sides to restart talk of renewing the START and INF treaties.”

That echoed his public call last year:

If the INF treaty could be saved, it would be a powerful signal for the whole world that the biggest nuclear powers understand their responsibility and take their obligations seriously.

Gorbachev argued then, as he did in our meeting, for a summit between President Donald Trump and Putin to discuss nuclear-arms control.

In my meetings with the foreign-affairs committees in Russia’s upper house, the Federation Council, and lower house, the State Duma, legislators also expressed an interest in holding formal talks to renew New START and continue the INF Treaty. I have invited members of both foreign-affairs committees to Congress this fall to continue these discussions. It is my hope that Democrats who have previously been supportive of nuclear-arms reductions will join in these meetings.

On the long flight home from Russia, as I was reading Eric Metaxas’s book Martin Luther, I realized that great challenges to orthodoxy are rare but necessary at times to right great wrongs or prevent great tragedy. I, for one, am thankful that Reagan and Gorbachev defied orthodoxy to cut stockpiles of nuclear weapons and reduce the tension between our countries. I hope thoughtful minds will prevail in our current standoff with Russia, and embrace the dialogue necessary to further reduce the potential for the terrible, world-altering catastrophe that a war between nuclear powers could bring.