This group was limited for a few years to conservatives and Republicans in Congress. But now a Democrat at the centrist Brookings Institution, Washington’s premier academic think tank, is joining the privatization side, arguing in a new paper that Congress’s inaction requires that something be done. Elaine Kamarck says that letting politicians continue to protect the Postal Service from competition is no longer viable.

“If the USPS were a purely private entity, the changing shape of the marketplace wouldn’t necessarily pose an existential threat,” Kamarck wrote in an essay made public last week, “Delaying the inevitable: Political stalemate and the U.S. Postal Service.”

“They could shrink the infrastructure created to deliver first-class mail and increase their capacity to deliver parcels,” she writes, “a logical adaptation to the changes that have come about as Americans have moved from paper to the Internet.”

The idea of selling off any part of the government agency for which Benjamin Franklin first served as postmaster general has drawn fierce opposition from Democrats in Congress and the still-powerful postal unions.