This claim is a fiction invented by The Daily Beast:

Oregon’s statehouse shut down for safety concerns on Saturday. But the threats weren’t coming from anonymous trolls or foreign fighters—they were coming from the state’s Republican senators, who have teamed up with right-wing militias to threaten violence over a climate change bill.

Source: Oregon Statehouse Shut Down After Lawmakers Flee, Team Up With Right-Wing Militias

From a reporter for The Oregonian newspaper:

This is now in The Oregonian newspaper too: Militia offer Oregon Senators ‘security,’ Republicans aren’t ‘accepting the help’

The Daily Beast made up their false claim about Oregon Republicans “teamed up” with right wing militia groups.

The way to respond to accusations of fictional news reporting is to double down on accuracy, objectivity and remaining calm. Unfortunately, the news industry continues to harm itself through self destructive behavior typical of middle school drama. If the news media wishes to be respected, then earn it. Stop engaging in this self destructive behavior.