Over the course of my career as an undercover officer in the C.I.A., I saw Russian intelligence manipulate many people. I never thought I would see the day when an American president would be one of them.

The president’s failure to defend the United States intelligence community’s unanimous conclusions of Russian meddling in the 2016 election and condemn Russian covert counterinfluence campaigns and his standing idle on the world stage while a Russian dictator spouted lies confused many but should concern all Americans. By playing into Vladimir Putin’s hands, the leader of the free world actively participated in a Russian disinformation campaign that legitimized Russian denial and weakened the credibility of the United States to both our friends and foes abroad.