On Wednesday, White House press secretary Sarah Huckabee Sanders said President Trump is still considering Russian President Putin’s request to allow Russian investigators to question U.S. citizens about supposed criminal activity relating to Bill Browder and those working with him.

Putin proposed it as a quid pro quo:

Russia would let special counsel Robert Mueller’s team indirectly question the Russian intelligence officers indicted for interfering in the 2016 U.S. elections. In return, Russia would get to question Americans associated with Bill Browder.

I am one of the Americans—apparently due to my work as a lawyer for Browder. Browder is a U.S.-born financier whose Russian lawyer, Sergei Magnitsky, died in a Moscow prison where he had been held since exposing a $230 million fraud against the Russian treasury carried out by a criminal organization operating in collusion with corrupt Russian officials. Magnitsky was held in custody for 358 days, tortured, denied medical care, and beaten to death in 2009. Then, the Russians tried and convicted him, posthumously, for the crime he had actually exposed.

When Browder consulted me, he wanted to know what he could do to hold those involved in the case accountable. As Browder describes in his book, Red Notice, I suggested creating a new law to impose economic and travel sanctions on human-rights violators involved in grand corruption. Browder decided this could secure a measure of justice for Magnitsky. He initiated a campaign that led to the enactment of the Magnitsky Act. Soon other countries enacted their own Magnitsky Acts, including Canada, Estonia, Latvia, Lithuania, and most recently, the United Kingdom.

In response, Putin and his Kremlin associates retaliated against Browder. The Russian government made a series of requests for his arrest, or Red Notices. These were repeatedly rejected by Interpol as politically motivated. Russian prosecutors also asked other countries to cooperate in other legal actions against Browder, which were rejected in country after country as political in nature.

Meanwhile, the Kremlin orchestrated an anti-Browder lobbying campaign. This effort culminated in the now-famous Trump Tower meeting of Russian representatives with Donald Trump Jr., Trump son-in-law Jared Kushner, and Trump campaign manager Paul Manafort on June 9, 2016, which the Russians secured by promising to provide dirt on Hillary Clinton. Instead, they used it to share bogus information on Browder and to lobby to repeal the Magnitsky Act.

Now President Putin has apparently sought to enlist President Trump in another round of retaliation against Browder, as well as the people who helped him, such as me; former U.S. Ambassador to Russia Michael McFaul; David Kramer, formerly the president of Freedom House and assistant secretary of state for human rights under George W. Bush; and senior Senate human-rights staffer Kyle Parker.

But neither Trump nor any other American president has any authority to force Americans to be interrogated by Russian officials. The only authority to do this stems from the Mutual Legal Assistance Treaty signed between the two countries in 1999. Under that treaty, Russia’s procurator general can ask the U.S. attorney general (not the president) to arrange for Americans to be ordered to testify to assist in a criminal case. But there is a fundamental exception: The attorney general can provide no such assistance in a politically motivated case.

I know this because I was among those who helped put it there. Back in 1999, when we were negotiating the agreement with Russia, I was the senior State Department official managing U.S.-Russia law-enforcement relations. We told the Russians explicitly in meetings in both Washington and Moscow then that we would not help Russia go after its political enemies. Indeed, the U.S. Senate would never have ratified such an agreement without this limitation, which at this point applies to any case involving Russia and Browder.

The State Department and the Justice Department, like the Congress, have already taken a stand as to what happened in the Magnitsky case and the nature of Russia’s case against Browder. For instance, in 2013, the Justice Department froze millions of dollars in assets in New York laundered by Russians relating to the fraud uncovered by Magnitsky. On Wednesday, a State Department spokesperson called the idea of the U.S. helping Russia interrogate U.S. citizens for their relationship to Browder “absolutely absurd.”

Just for the record, there are also our courts. If any U.S. president ordered any Justice Department to enforce this kind of foreign request, a federal judge would surely order them to stand down due to the political nature of the case—as illustrated by the very fact that a U.S. president had requested it as a favor for a foreign head of state.

Our system, unlike the one under Putin, is based on respect for rule of law, even under a president like Donald Trump.

Jonathan M. Winer is the former U.S. deputy assistant secretary of state for international law enforcement .