The starkest suggestion yet of collusion between the Trump campaign and Russia has come from the president's son himself.

At the end of an extraordinary series of events propelled by dogged New York Times reporting, Donald Trump Jr. has released an e-mail exchange that preceded his meeting in June 2016 with a Kremlin-­connected attorney promising incriminating information about Hillary Clinton.

"This is obviously very high level and sensitive information but is part of Russia and its government's support of Mr. Trump," a Russian intermediary wrote.

The "Mr. Trump" in question is now President Donald Trump, who has denied any campaign collusion, a claim becoming more unbelievable daily.

The legality of Trump Jr.'s enthusiastic seeking of such dubious goods — "If it's what you say I love it especially later in the summer," Trump Jr. responded on June 3, 2016 — will be evaluated by Robert Mueller, the former FBI director who is now special counsel investigating the enduring and burgeoning allegations. Clearly, the proposal of such a meeting should have triggered a call to the FBI, not a gleeful acceptance.

Ethically, meanwhile, the issue is unambiguous: It's rotten to degrade our democracy by seeking "opposition research" from a foreign operative representing a Russian government that has annexed Crimea, destabilized eastern Ukraine, kept the heinous Assad government in power in Syria, suppressed its own citizens' human rights, and attempted repeatedly to divide Western societies through election meddling and propaganda dissemination.

Trump Jr. said he released the e-mail trail Tuesday in a bid to be "transparent." But he's been anything but that, mischaracterizing these events repeatedly and changing his story with every revelation. Other administration figures have also been serially dishonest, including two who attended the meeting: Jared Kushner, Trump's son-in-law who still holds a national-security clearance despite lying about his contact with Russians, and Paul Manafort, Trump's former campaign manager with extensive Russian ties.

It's also hard to have confidence in the president, on either the collusion question or the broader U.S.-Russia relationship, which was badly managed in Trump's meeting with Russian President Vladimir Putin at last week's G-20 summit. Indeed, the revelations regarding the younger Trump make it even harder to believe the administration's version of just how hard Trump pushed Putin on election interference.

That poor performance came after Trump, on foreign soil, denigrated U.S. intelligence agencies' unanimous analysis of Russia's interference in our election, and before his proposal to form a cybersecurity partnership with Russia, an idea so absurd that Trump had to tweet a reversal after key congressional leaders, on a bipartisan basis, howled in opposition.

The president and his close associates won't come clean without Congress, the special counsel and the press asking the questions that deserve answers. They must keep pressing until the full truth is revealed.