I would work very diligently to avoid becoming the test case in federal court.
The good folks of Newton County, Missouri might not complain too much about the first quarter million in legal defense costs for their sheriff, but it probably won't be long until passing the hat around doesn't raise much more cash.
You don't go up for trial in federal court against a team of assistant US attorneys with a good old boy country lawyer handling your defense. You need several top-shelf trial lawyers (along with their staffs) and a parade of expert witnesses (in such a case as this you'd better have recognized constitutional scholars), and none of those folks show up for chump change. Fees won't be measured in hundreds of dollars per hour, you'll be looking at multiples of thousands every week and month for a year or two, even if you don't have to file appeals. Meanwhile, the good sheriff will be under federal indictment, prohibited from possessing firearms or leaving the state until the fat lady sings to the judge's satisfaction.
I sincerely hope the sheriff receives very good legal advice before embarking on enforcement of the new county ordinance. Probably wouldn't hurt to listen to his wife, too. A well-timed vacation, maybe a remote lake with no phones or cellular service, could work nicely.