Beginning of the end?

Despite suggestions by the White House that it’s no big deal, the guilty plea by former national security advisor Michael Flynn to a charge of lying to the FBI about his conversations with a Russian diplomat is an ominous and dramatic development in special counsel Robert S. Mueller III’s critically important investigation. During the hearing at which Flynn pleaded guilty, a federal judge disclosed that the retired three-star Army general had agreed to cooperate fully with prosecutors, providing information on “any and all matters” they request, and “substantial assistance for prosecution of another person.”

That doesn’t necessarily mean that Flynn will produce evidence implicating President Donald Trump or other administration officials in criminal wrongdoing. But it certainly bodes badly for the White House, and provides further evidence that the inquiry into what Trump has dismissed as a “hoax” is a serious one. It must be allowed to run its course without further interference from the White House.

For those keeping score, Mueller’s team has in recent weeks brought felony charges against Trump’s former campaign chairman and two other campaign aides. Now, he’s charged Trump’s former national security advisor as well. Could the noose be tightening?

Flynn’s guilty plea arises from conversations he had with Russian Ambassador Sergey Kislyak after the election.

Flynn lied about those conversations. First he denied to the FBI that he had asked the Russian government to hold off on retaliating against sanctions imposed by President Obama for Russian meddling in the U.S. election. He also lied about a conversation in which he requested that Russia defeat or delay a vote on a U.N. Security Council resolution criticizing Israel for its settlements on the West Bank.

By lying about his contacts with the ambassador, Flynn compromised his effectiveness in government as well as placing himself in legal jeopardy.

In fact he made both requests — and he did so during the presidential transition, before Trump was sworn into office. Attempts by an incoming administration to interfere in the conduct of foreign policy are unseemly, and they may also be illegal. Under a 1799 federal statute known as the Logan Act, it’s a crime for a private citizen to negotiate with a foreign government.

The Logan Act is generally regarded as a dead letter, but by lying about his contacts with the ambassador, Flynn compromised his effectiveness in government as well as placing himself in legal jeopardy. On Feb. 13, after less than a month as national security advisor, he was fired by Trump for misleading Vice President Mike Pence about those conversations.

Responding to Flynn’s plea, Ty Cobb, Trump’s lawyer, tried to minimize its significance, noting that “nothing about the guilty plea or the charge implicates anyone other than Mr. Flynn.”

That’s true, but Mueller must believe that Flynn can provide useful information about other matters, or he would not have cut Friday’s deal. Those matters could include possible collusion between the Trump team and Russia during the campaign and whether Trump engaged in obstruction of justice when he fired former FBI Director James B. Comey. (According to Comey, Trump told him, “I hope you can see your way clear to letting this go, to letting Flynn go.” Comey told a Senate committee that he regarded that as “a direction.”)

Although Cobb said he hoped for a “prompt and reasonable conclusion” to Mueller’s investigation, there may be more pleas and prosecutions to come and, if the past is any guide, Trump may become frustrated and resentful. It’s vital that he not attempt to interfere with this crucial investigation either by the use of his pardon authority or by firing Mueller. The president’s lawyers and other advisors need to remind him that succumbing to any such temptation would escalate calls for his impeachment and removal from office.