As part of his “drain the swamp” campaign promises, in January US president Donald Trump signed an executive order to limit conflicts of interest. It required all his appointees not to deal with matters relating to people they had worked with up to two years before their appointment.

A thoroughly sensible policy. Except it turns out that one of the main people charged with overseeing it, and other White House ethics issues, is in violation of it. The financial disclosure form (pdf) of Stefan Passantino, a deputy White House counsel and the White House’s “designated agency ethics official,” reveals that within the last two years he’s done paid work for housing secretary Ben Carson, health secretary Tom Price, and, much to Democrats’ chagrin, the unpaid ”special adviser to the president,” Carl Icahn.

Icahn, a billionaire investor who came to Trump’s rescue when his Atlantic City casinos hit rock bottom, has been the target of consistent ethics complaints alleging that his role as a regulatory adviser—particularly on environmental issues—directly benefits his energy investments. Since Icahn is unpaid, he doesn’t have to disclose his financial interests—worth $15.8 billion according to Forbes.

The mogul has brushed off the complaints, telling CNN in March that “we vetted this with the lawyers a number of times. I think the criticism is nonsense.” Passantino would presumably have been one of the lawyers in charge of that vetting.

In a letter on April 21, Democratic senators Elizabeth Warren and Sheldon Whitehouse wrote to Passantino (pdf) to request details on his prior services to Icahn, and whether he has worked on matters relating to Icahn, Carson, and Price while in the White House.

The White House did not respond immediately to a request for comment on the letter, or on whether Passantino has recused himself from matters relating to those three—we will update if they do.