Senator Bob Menendez (D., N.J.) hired a longtime aide and lobbyist for the Qatari government to chair his reelection campaign, the Philadelphia Inquirer reported Friday.

Michael Soliman has lobbied Menendez, the top Democrat on the Foreign Relations Committee, and other lawmakers on behalf of the Qatari government since 2015.

While the arrangement is strictly legal, ethics experts told the Inquirer that it might constitute a conflict of interest.

“There is a blurring of lines between responsibility to the candidate and responsibility to their client,” said Meredith McGehee of the Campaign Legal Center, a nonprofit watchdog in Washington. “Very little of that is a responsibility to the public.”