Below is my column in The Hill newspaper on the issuance of a subpoena to the Trump organization for records pertinent to Trump business dealings in Russia.  President Trump previously responded to a question of whether such inquiries into his business dealings would be a “red line” by saying that it would.  Whether it is a red line or a “Rubicon,” Mueller seems to have crossed it.  Of course, the Trump Organization has been asked for information previously and it is cooperating. However, this is a direct demand for business records.  In the best case scenario, this could be a clean up subpoena to guarantee that all available documents have been reviewed.  Then again it might be a new front in the investigation.  Notably, this weekend, President Trump and his counsel ramped up their criticism of the investigation — criticism that I continue to view as unwise and inappropriate.

Here is the column:

Politicians seem to be drawn to red lines the way tornados are drawn to mobile homes, and the results are just about the same.

Red lines are the favorite way for politicians to distinguish between their usual hyperbolic language and a final ultimatum. It is the way for politicians to say, “I really mean it,” and can often prove embarrassing when they don’t.

That was the problem when President Barack Obama drew his “red line” in 2012 on the use of chemical weapons by the Assad regime in Syria. Bashar Assad used chemical weapons, and Obama did effectively nothing.

Donald Trump legitimately criticized Obama for that blunder, but now Trump has his own red line problem.

Special counsel Robert Mueller has issued a subpoena to the Trump Organization to turn over documents related to Trump’s business interests in Russia. In July, Trump was asked if investigating his finances would be a “red line,” and he responded that it would be. Now that Mueller has sent a subpoena flying over that red line, the stakes could not be higher for Trump.

The investigation is obviously not wrapping up, as suggested by the White House, and it is moving into an area rife with risk for the president. The greatest risk, however, is not Mueller’s but Trump’s possible actions.

There is no question that Mueller is now fishing in waters far afield from the original allegations of collusion on Russia, but this subpoena is well within his mandate. Mueller is allowed to investigate “any links and/or coordination between the Russian government and individuals associated” with the Trump campaign, as well as “any matters that arose or may arise directly from the investigation.” Trump’s former associates effectively made the nexus needed by Mueller to pursue this information.

The subpoena reportedly includes business dealings in Russia and related topics. One obvious focus of the investigators is likely to be the 2015 venture to build a Trump Tower in Moscow. Ultimately, nothing came from the effort, but Trump was personally consulted on the venture and the company issued an initial non-binding “letter of intent.”

At the heart of the venture was a fairly shady character named Felix Sater, who wrote to Trump’s equally controversial lawyer, Michael Cohen, to push a deal in Moscow. Of particular note is the timing of this email during the presidential campaign; in one of Sater’s emails to Cohen, Sater assured that “Our boy can become president of the USA and we can engineer it. I will get all of Putins team to buy in on this, I will manage this process.”

A Russian immigrant, Sater often bragged of his contacts in Russia and Putin’s inner circle. He was particularly proud of arranging a 2006 trip by Ivanka Trump to Russia and “arrang[ing] for Ivanka to sit in Putins private chair at his desk and office in the Kremlin.”

Sater had worked with Trump on other projects. He is often described by critics as someone with an uncontrollable temper and insatiable greed; he once reportedly stabbed a man in the face with a martini glass stem. Sater assured the Trump team that “I will get Putin on this program and we will get Donald elected.” Sater laid out how Putin could help Trump by using the deal to portray Trump as a business genius: “If he says it we own this election. Americas most difficult adversary agreeing that Donald is a good guy to negotiate.”

Sater was writing during the campaign about a Russian deal but selling the deal as a way for Putin to help Trump. He even laid out his own cut in an email in saying that he wanted the ambassadorship to the Bahamas: “That my friend is the home run I want out of this.”

Sater could be the “home run” for Trump critics, however. The financing laid out by Sater would have come from Vneshtorgbank, or VTB, a Russian bank already under sanctions by the United States for funding an effort to undermine Ukraine’s political system.

Mueller may also pursue other financial leads, particularly in light of his prior subpoenas to Deutsche Bank for records pertaining to Trump associates and deals. VTB has been linked to Deutsche Bank in shady deals out of Moscow; Deutsche Bank was a central player in laundering Russian money worldwide. Trump reportedly owed the bank $300 million at the time of his taking office. New York Department of Financial Services fined the bank $425 million just after Trump inauguration.

As usual, there has been a degree of hyperventilation over this new subpoena, and it is important to keep the inquiry in perspective. The Moscow deal ultimately fell through, and even some of the cited evidence cuts both ways for Trump. For example, Cohen’s involvement is hardly notable given his reckless and self-defeating moves in the Stormy Daniels controversy; Cohen is cited as trying to reach out to Putin’s spokesman, Dmitri S. Peskov, to ask Putin to help on the Trump Tower deal.

It certainly sounds like vintage Michael Cohen, who professionally shows all of the control of a falling locomotive. However, Cohen notably did not even have Peskov’s direct email, and sent this highly controversial email to a general inbox for press inquiries. That was like using Facebook to arrange collusion meetings and asking a possible co-conspirator to “friend” you with a call-me emoji.

With the likes of Sater and Cohen working together, the results are likely to be more comical than conspiratorial. Nevertheless, there are risks (as I have previously raised) in Mueller combing through Trump financial deals.

But the biggest risk could be self-inflicted: One month before stating this red line, Trump reportedly ordered White House counsel Donald F. McGahn II to fire Mueller. McGahn refused, and ultimately threatened to resign.

If Trump were to fire Mueller at this point, it could deliver not just a “home run” but the game to critics. Trump blundered by firing Comey and triggering the special counsel appointment. The firing of Mueller would be a hundred times worse for the White House and present a true existential threat to this administration. Congress would likely move to reinstate the Independent Counsel Act or otherwise protect Mueller.

That is Congress’s red line, and no one has to state it.

Jonathan Turley is the Shapiro Professor of Public Interest Law at George Washington University. You can follow him on Twitter @JonathanTurley.