(Bloomberg View) —It’s fashionable among President Donald Trump’s defenders to dismiss the reports of his eldest son meeting with a Russian lawyer who promised damaging information on Hillary Clinton as yet another “nothing burger.”

You’ve heard the counterpoints. The Democrats are obsessed with the Kremlin. Nothing came of the Russian attempt to dish dirt. Donald Jr. made all his e-mails about it public. And, hey, whatever happened, it’s probably not even illegal

And while all of that is likely true, it misses a broader point. The e-mails the younger Trump received from music promoter Rob Goldstone, who promised official Russian “documents and information that would incriminate Hillary,” may have just been an opportunist trying to curry favor with the presumptive Republican presidential nominee. But Goldstone’s successful effort to set up a meeting between members of the campaign’s inner circle and a lawyer with Kremlin connections puts the lie to Team Trump’s longtime defense in the brewing scandal: no contact, no collusion.

As someone who has written columns pointing out that many claims against Trump and his advisers have been speculative and unsubstantiated, I see this supposed nothing burger as a tipping point. From now on, it strains credulity to give the president and his aides any benefit of the doubt when it comes to Russia. After all, a little more than a month after his June 9, 2016, meeting with Kremlin insider Natalia Veselnitskaya, the president’s son was on CNN saying the entire Russia allegation was fake news. That line is no longer operative.

The best course now for the president would be full disclosure. He needs to tell us about any and all meetings his campaign and organization has had with Russians. If there was an offer of a heads-up on hacked e-mails — or, as McClatchy is reporting, a plan to coordinate with Russian fake news bots to target voters through data operations — he needs to acknowledge and apologize.

That said, Democrats should be careful. One element of the Russian influence operation that is often overlooked is that it was intended to sew discord inside the U.S. body politic and discredit our democratic elections. Recall that the initial probing of Democratic National Committee computers by Russian hackers began in 2015, when no one believed Trump would even be the nominee.

As former FBI director James Comey testified in March, the hackers were unusually sloppy, leaving many clues for investigators to trace the hacks back to Russia. They “wanted us to see what they were doing,” Comey said.

In this respect, the partisan temptation to overstate the case against the president should be resisted. Unfortunately, many Democrats have gone the opposite route. Senator Tim Kaine, who was Hillary Clinton’s running mate, said this week that the Trump Jr. e-mail exchange may be evidence of treason. Representative Seth Moulton of Massachusetts went further saying if the emails are not treasonous, “I’m not sure what is.”

Kaine and Moulton should consult the Constitution on this question. Treason is defined narrowly and applies only to aiding and abetting an enemy at a time of war. At this point, considering that all people in the meeting have said the promised information on Hillary Clinton was never offered, it’s not even clear if this is collusion.

This kind of hyperventilation is the analog of Trump’s campaign against the “fake news media.” It energizes loyalists at the expense of national unity, which is especially worrisome now, in an America so divided and at each other’s throats.

It reminds me of one of the most toxic episodes of Trump’s presidential campaign. In the final debate, he would not say whether or not he would accept the results of the election. “I will keep you in suspense.”

It turned out that it was the Trump resistance that never really accepted him as a legitimate president. Armed with suspicion, leaks, open questions and an opposition research dossier, Democrats beat the drum for months that Trump was the Siberian candidate.

Now it turns out the president’s son was eager and willing to accept information that was promised as part of a Russian government effort to aid his father’s campaign. This doesn’t prove the Democratic narrative about Trump. But it does discredit the evasions, denials, obfuscations and dissembling from the president and his supporters. We have reached the point where Trump must come clean. If he doesn’t, he will be abetting a Russian plot to discredit the election they tried to help him win.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.