There are exactly two possible explanations for the shameful performance the world witnessed on Monday, from a serving American president.
Either Donald Trump is flat-out an agent of Russian interests—maybe witting, maybe unwitting, from fear of blackmail, in hope of future deals, out of manly respect for Vladimir Putin, out of gratitude for Russia’s help during the election, out of pathetic inability to see beyond his 306 electoral votes. Whatever the exact mixture of motives might be, it doesn’t really matter.
Or he is so profoundly ignorant, insecure, and narcissistic that he did not realize that, at every step, he was advancing the line that Putin hoped he would advance, and the line that the American intelligence, defense, and law-enforcement agencies most dreaded.
Conscious tool. Useful idiot. Those are the choices, though both are possibly true, so that the main question is the proportions.
Whatever the balance of motivations, what mattered was that Trump’s answers during his joint press conference with the Russian president were indistinguishable from Putin’s, starting with the fundamental claim that Putin’s assurances about interference in U.S. democracy (“He was incredibly strong and confident in his denial”) deserved belief over those of his own Department of Justice (“I think the probe is a disaster for our country”).