Bernd Debusmann is a Reuters columnist. The opinions expressed are his own.

Who says that the United States and Iran can't agree on anything? The Great Satan, as Iran's theocratic rulers call the United States, and the Islamic Republic see eye-to-eye on at least one thing, that the Iranian opposition group Mujahedin-e-Khalq (MEK) are terrorists.

America and Iran arrived at the terrorist designation for the MEK at different times and from different angles but the convergence is bizarre, even by the complicated standards of Middle Eastern politics. The United States designated the MEK a Foreign Terrorist Organization in 1997, when the Clinton administration hoped the move would help open a dialogue with Iran. Thirteen years later, there is still no dialogue.

But the group is still on the list, despite years of legal wrangling over the designation through the U.S. legal system. Britain and the European Union took the group off their terrorist lists in 2008 and 2009 respectively after court rulings that found no evidence of terrorist actions after the MEK renounced violence in 2001.

On July 16, a federal appeals court in Washington instructed the Department of State to review the terrorist designation, in language that suggested that it should be revoked. But Hillary Clinton’s review mills appear to be grinding very slowly.

A group of lawmakers from both parties reminded Clinton of the court ruling this week and drew attention to a House resolution in June -- it has more than 100 co-sponsors and the list is growing -- that called for the MEK to be taken off the terrorist list. Doing so would not only be the right thing, the six leading sponsors said in a letter, it would also send the right message to Tehran. Translation: using the terrorist label as a carrot does not work, so it's time to be tough.