Donald Trump and Michael Flynn at a rally in October in Colorado. (George Frey/Getty Images)

At the center of so many political — and now possibly legal — controversies of the Trump administration is one man: retired Lt. Gen. Michael T. Flynn.

Flynn, Trump's national security adviser during the transition and for less than a month during his presidency, was involved in a lot of questionable Trump administration actions, including:

  • Repeatedly talking with the Russians despite warnings from others on Team Trump not to (and despite the White House denying in January that it had contacts with Russian officials during the campaign).
  • Misleading the White House about the nature of those conversations with the Russians once those conversations became public. Vice President Pence said on TV that Flynn didn't discuss U.S. sanctions with the Russian ambassador to Washington. But the FBI was monitoring Flynn's conversations with the Russians, and it turns out that, yes, he did discuss U.S. sanctions.
  • Continuing, for 18 days, to be Trump's national security adviser despite warnings from the top Justice Department official at the time, Sally Yates, that the Russians knew Flynn was lying about his conversations and, thus, had leverage over him.
  • Was the person Trump pressured then-FBI Director James B. Comey to lay off investigating, according to Comey's notes. (Flynn “is a good guy,” Comey recalled the president as saying to him.)

But perhaps the most damning of all of Flynn's troubles — and the one that could keep haunting the Trump administration — is something that has little to do with Russia: Flynn was working for the Turkish government while working for Trump, which means that he was advocating for policies that benefited Turkey while serving as Trump's national security adviser. And Trump may have known about this.

Those revelations are from reports late Wednesday published by McClatchy and the New York Times, respectively. Taken together, they're damning because what Flynn did gets at the heart of being a democracy: He was on the payroll of a foreign government while in a powerful position in the U.S. government.

The Pentagon's inspector general launched an investigation into Gen. Michael Flynn over payments he accepted from foreign governments. The revelation came on April 27, when House Democrats released a letter sent from Defense Department Inspector General Glenn A. Fine to the House Oversight Committee. (Reuters)

Lobbying for a foreign government while simultaneously working for the U.S. government crosses just about every ethical red line you can think of, experts say.

Texas Gov. Greg Abbott (R) just fired a top state official because the official didn't tell Abbott that he was also working for the Iraqi government. When that happened, I talked to Meredith McGehee with the Campaign Legal Center about why such dual roles are a fireable offense. She explained:

“There's recognition that there are competing interests and a number of potential conflicts that arise between one government and a foreign government,” McGehee said. “That's just kind of built into a system, where a public servant is supposed to be serving the American people, not serving a second master.”

She added: “Can you imagine a U.S. senator saying, 'Oh, yeah, I'm a U.S. senator and, at the same time, I'm lobbying on behalf of Mexico'?"

As for how this ties to Trump, the New York Times reports that Flynn told the president's transition team weeks before the inauguration that the Justice Department was looking into his undisclosed lobbying for Turkey. So it's very possible that Trump knew Flynn had financial ties to the Turkish government when the president hired Flynn as his top adviser on national security.

As McClatchy reports, the potential conflicts involving Flynn started almost immediately. He wrote an opinion piece for the Hill on Election Day titled, “Our ally Turkey is in crisis and needs our support.” Here's a snippet:

 

And, as McClatchy reports, the Turkish-U.S. Business Council moved its annual summit from the Ritz-Carlton to the Trump International Hotel in Washington.

The United States has a law — the Foreign Agent Registration Act — to prevent this sort of conflict. It says U.S. citizens who lobby for foreign governments have to tell the Justice Department about it. Flynn didn't do that. He didn't disclose his lobbying work to the federal government, nor to Trump (at least immediately). Flynn, as a former military official, also has to get the military's permission to do this kind of lobbying work.

“The notion you would be working for any government entity and also lobbying on behalf of a foreign government is quite concerning,” McGehee said. 

For all of the above, Flynn is at the center of myriad investigations.

Federal prosecutors are looking into whether he broke the law by not disclosing his lobbying work for foreign governments (he was also paid $45,000 for an appearance on Russian TV). This month, they subpoenaed his associates for more information. The Defense Department's internal watchdog is investigating Flynn's undisclosed lobbying work, as well.

Notes by former FBI director James B. Comey show President Trump wanted the probe into former national security adviser Michael Flynn dropped. (The Washington Post)

It's highly likely that Flynn is a key factor in the FBI's investigation of Russian meddling in the U.S. election and any possible ties between Trump associates and Russia during the 2016 campaign.

What Trump knew about Flynn's dual roles will probably be of keen interest to the special counsel the Justice Department appointed Wednesday to lead the Russia investigation. Did Trump know Flynn was also working for a foreign government? And if so, what does that say about the administration's intentions toward other governments, including Russia's? Add to all this the fact that Trump revealed classified information to Russian officials this month.

Those questions are why Flynn's decision to lobby for Turkey and work for Trump at the same time could indefinitely haunt the Trump administration.