As the NATO summit comes to an end, the focus turns to President Trump’s upcoming meeting with Vladimir Putin. Congress has shown that our NATO alliance remains paramount, and President Trump ultimately expressed his support to our allies by signing the Brussels Summit Declaration. Now is the time for the president to convey to Putin that duplicitous behavior is unacceptable and our long-term commitment to NATO will not waver.

I recently returned from meetings in Moscow, Oslo, and Helsinki, where everything I heard reinforces my belief that a unified NATO alliance is essential to American security and prosperity. The concerns relayed to me by European leaders underscore the fear our European friends have about Russia’s activities. My colleagues and I reassured them of America’s commitment to our joint security during our meetings, and additionally, the Senate this week overwhelmingly passed a motion that reaffirms our nation’s assurance to NATO.

Putin is not our friend – he is an adversary intent on continuing Russia’s disruptive activities in Europe and the Middle East, and against us here at home. Throughout Europe, Russia funds efforts to undermine the sanctions jointly imposed by the United States and Europe. In the Middle East – both in Syria and Libya – Russia’s involvement is escalating the refugee crisis Europe is struggling to contain. Further afield, our military leaders testify, Moscow is supporting the Taliban in Afghanistan. And of course, Russia interfered with our own democratic process in 2016 and will continue the same efforts in upcoming elections.

I share President Trump’s desire for better relations with Russia. My purpose for traveling to Moscow was to begin a dialogue to explore how we can develop a responsible relationship. In every meeting I attended in Moscow, I made clear the Russians must end their election meddling here in the United States and Europe in order to open the door to rebuilding relations. I brought up Russia’s destabilizing support for separatists in Ukraine and its illegal seizure of Crimea after Ukraine democratically chose a president who sought closer ties to the West. Its support for the Taliban undermines the democratic government in Afghanistan. In every circumstance, Russian officials, including Foreign Minister Sergey Lavrov, continued to obfuscate or outright deny any responsibility. However, those meetings left me unconvinced that Russia is prepared to change its behavior.

I encourage President Trump to make certain he has trusted advisors in the room to prevent Russian attempts to deceive or misrepresent the authenticity of what is discussed. We’ve long known the Russians are skilled propagandists, and this was reaffirmed by the way they spun and misled media regarding the nature of my meetings in Moscow.

The first Supreme Allied Commander Europe overseeing all NATO military operations was Kansas’s own Dwight D. Eisenhower. As president in 1957, he declared before our NATO allies that we must “re-dedicate ourselves to the task of dispelling the shadows that are being cast upon the free world.” Terrorist groups remain intent on striking the West; threats to data information require strong cybersecurity measures; and the scourge of human and drug trafficking degrade social structures. On these and other issues, NATO allies have coordinated and contributed to the security of our nation. In particular, we owe a debt to the NATO coalition forces who have been killed or wounded and continue to fight alongside ours in Afghanistan.

I thought of the force for good our country has provided the world as I stood in our embassy in Moscow on July 4, watching the Marine Corps Honor Guard’s presentation of the colors as our national anthem played. I reflected on the course of events in my life, when my classmates and I practiced getting under our desks for missile drills in rural Kansas, to the fall of the Berlin Wall, to the aftermath of 9/11. Over the past 70 years, it is America that has safeguarded freedom for her people and those around the world. Along the way, our vision of a freer, more prosperous world attracted allies who shared that dream. NATO allies have supported us up to now. For our nation’s security, it is critical President Trump reiterates to Putin that NATO is unified and we are determined to protect our freedoms and defeat any threat to our way of life.