The 9,700 National Guard soldiers protecting the U.S. Capitol from “domestic violent extremists” face increasing pressure to return home as COVID infections sideline hundreds of troops and freezing temperatures descend on Washington.

The deployment threatens to become yet another hot-button political issue, with some Republican lawmakers beginning to raise doubts about any need for their presence. GOP members could feel pressure from conservative opinion-makers like Fox News evening host Tucker Carlson, who used part of his Wednesday show to call what the Guard is doing in the nation’s capital an “occupation.”