The next question is whether Russia was also behind the release of the stolen emails to WikiLeaks. Someone using the name Guccifer 2.0 claimed to be behind the hack, denied Russian involvement and claimed to be Romanian — but wrote Romanian badly. ThreatConnect, a private security firm, issued a meticulous report showing that Guccifer used a Russia-based VPN (virtual private network) service and displayed other “heavy traces of Russian activity.”

“Guccifer 2.0 is a Russian propaganda effort,” ThreatConnect concluded.

After talking to experts, I have the sense that there’s considerable confidence that Russia is the culprit, but more doubt about whether Putin gave the order and about whether the aim was to benefit Trump or simply to create havoc.

“I think the most likely explanation is that someone in Russian intelligence, probably very high up, decided to help Donald Trump,” said Benjamin Wittes, a security expert at the Brookings Institution, but he added that there’s no solid evidence for this.

One reason for caution is that history shows that “intelligence community” is sometimes an oxymoron. In the 1980s, the United States accused Russia of conducting chemical warfare in Southeast Asia, citing “yellow rain” in jungles there. Years later, it turned out that this “yellow rain” may have actually been bee excrement.

Democrats should be particularly wary of hinting that Trump is some sort of conscious pawn of the Russians, or is controlled by Moscow through financial investments. It’s true that his son Donald Trump Jr. said in 2008 that “we see a lot of money pouring in from Russia.” But do you really think that if Trump were an agent he would have exaggerated his ties, as he did last year, saying of Putin, “I got to know him very well”? In fact, Trump acknowledged Wednesday, he has never even met Putin.

The reason Moscow favors Trump isn’t some conspiracy. It’s simply that Putin dislikes Clinton, while Trump’s combination of international ignorance and catastrophic policies would benefit Putin. In particular, Trump’s public doubts about NATO renounce more than half a century of bipartisan orthodoxy on how to deal with Russia, and undermine the Western alliance that checks Putin.