The federal government is now petitioning to have these signs removed or Washington state will be denied additional monies for interstate highways.
The State of Washington replied, they will secede from the Union rather than be intimidated. These are a matter of free speech paid for by a private citizen.
It seems the Obama government uses intimidation and ignores the first amendment, when they want to silence someone.
Northbound on I-5, near Chehalis, WA (88 miles south of Seattle)