If the bloody debacle in Iraq should have taught Americans anything, it is that endorsements by lots of important people who think something is true don't amount to evidence that it actually is true. If endorsements were the same as evidence, U.S. troops would have found tons of WMD in Iraq, rather than come up empty.

Russian President Vladimir Putin meets with U.S. President Donald Trump at the G-20 summit in Hamburg, Germany, on July 7, 2017. (Screen shot from Whitehouse.gov)

So, when it comes to whether or not Russia "hacked" Democratic emails last year and slipped them to WikiLeaks, just because a bunch of people with fancy titles think the Russians are guilty doesn't compensate for the lack of evidence so far evinced to support this core charge.

But the reaction of Official Washington and the U.S. mainstream media to President Trump saying that Russian President Vladimir Putin seemed sincere in denying Russian "meddling" was sputtering outrage: How could Trump doubt what so many important people think is true?

Yet, if the case were all that strong that Russia did "hack" the emails, you would have expected a straightforward explication of the evidence rather than a demonstration of a full-blown groupthink, but what we got this weekend was all groupthink and no evidence.

For instance, on Saturday, CNN responded to Trump's comment that Putin seems to "mean it" when he denied meddling by running a list of important Americans who had endorsed the Russian-guilt verdict. Other U.S. news outlets and politicians followed the same pattern.

Rep. Adam Schiff of California, the ranking Democrat on the House Intelligence Committee and a big promoter of the Russia-gate allegations, scoffed at what Trump said: "You believe a foreign adversary over your own intelligence agencies?"

The Washington Post's headline sitting atop Sunday's lede article read: "Trump says Putin sincere in denial of Russian meddling: Critics call that 'unconscionable.'"

Sen. Mark Warner of Virginia, the ranking Democrat on the Senate Intelligence Committee and another Russia-gate sparkplug, said he was left "completely speechless" by Trump's willingness to take Putin's word "over the conclusions of our own combined intelligence community."

Which gets us back to the Jan. 6 "Intelligence Community Assessment" and its stunning lack of evidence in support of its Russian guilty verdict. The ICA even admitted as much, that it wasn't asserting Russian guilt as fact but rather as opinion:

"Judgments are not intended to imply that we have proof that shows something to be a fact. Assessments are based on collected information, which is often incomplete or fragmentary, as well as logic, argumentation, and precedents."

Even The New York Times, which has led the media groupthink on Russian guilt, initially published the surprised reaction from correspondent Scott Shane who wrote: "What is missing from the public report is what many Americans most eagerly anticipated: hard evidence to back up the agencies' claims that the Russian government engineered the election attack. … Instead, the message from the agencies essentially amounts to 'trust us.'"

In other words, the ICA was not a disposition of fact; it was guesswork, possibly understandable guesswork, but guesswork nonetheless. And guesswork should be open to debate.