Oregon citizens and state troopers are keeping an eye peeled for AWOL Republican state senators who by being absent from their legislative jobs are stonewalling a vote on stricter pollution standards to battle climate change.

All 11 of the chamber’s GOP senators walked out of a legislative session Thursday and are in hiding to block passage of the historic bill. They don’t have the votes to stop it the old-fashioned, democratic way. The walkout leaves the Senate two people short of a required quorum before a vote can be held.

A rightwing militia group has vowed to “protect” the senators from any miffed voters — or police. A special legislative session had been planned Saturday but the Capitol building in Salem was shut down by law enforcement authorities as a safety precaution, Reuters reported.

The State Police superintendent informed the Senate president of a “credible threat from militia groups coming to the Capitol,” read a text sent to senators Friday, The Wall Street Journal reported. “The superintendent strongly recommends that no one come to the Capitol.”

Several senators have claimed they left the state to avoid detection by state troopers, who have been ordered to retrieve them by Gov. Kate Brown (D). Police said that “outside” agencies are helping them keep tabs on the errant senators.

Members of the Three Percenters militia ― an anti-government extremist movement ― wrote on Facebook Thursday they would do “whatever it takes to keep these senators safe.”

A leader with another rightwing militia, the Central Oregon Constitutional Guard, posted on Facebook that he spotted Republican state Sen. Dennis Linthicum of Klamath Falls gobbling up bacon and eggs at a diner in Redmond, Oregon, Saturday morning. (The militia member said later in a comment on the original post that he had made up the incident, claiming it was “satire.”)

GOP senators face a $500 fine for every session they miss. The Legislature is scheduled to recess at the end of June.