Sensing an opening, both Bennet and Senator Elizabeth Warren have taken Trump’s proposal a (giant) step further by calling for a lifetime lobbying ban. “Outside of Washington, the American people understand that it is neither partisan nor unreasonable to demand members of Congress, heads of government agencies, and the president of the United States not cash in on their unparalleled access to influence government policy for the highest bidder,” Warren said in an emailed statement.

But she and Bennet may find that convincing Congress to appropriate trillions of dollars for new social programs is an easier lift than persuading lawmakers to permanently cut off a lucrative source of their own retirement income. That idea goes too far even for the purest good-government advocates, who say it’s not only wildly unrealistic but possibly unconstitutional.

The last serious effort to extend the cooling-off period for members of Congress—long pegged at one year for both chambers—came in 2007 during debate over the Honest Leadership and Open Government Act, the ethics law that stemmed from the corruption scandal involving the prominent über-lobbyist Jack Abramoff, who pleaded guilty to bribing members of Congress and defrauding Native American tribes. Lawmakers had agreed to lengthen the ban for senators to two years, but a rebellion in the House nearly killed the entire bill, recalled Craig Holman of Public Citizen, the liberal group that advocates for consumer rights and government reform, among other issues. As a result, the cooling-off period for House members stayed at one year.