Although it sounds great on the surface, I'm not sure how this will play out in a real-world scenario. Whenever a state law falls in conflict with a federal law, the federal law will prevail. So, Wyoming's legislation may be nothing more than a symbolic gesture.
That said, if Texas and other red states join Wyoming and pass similar statutes, it will create a nightmare for the federal enforecement of any gun restrictions. Count me as another supporter of states rights in this matter.
You can look at the States that have medical marijuana and now legal marijuana to see how the fed reacts. Difference here is that WY wants to arrest the feds if they interfere. Could be interesting.
Of course, it all depends on how badly the US wants to enforce the mandate. If the Dems win the mid-term elections in 2 years and take back the House, they could really create some havoc.
Remember back in the mid-50s when the federal court ordered the forceful integration of Little Rock Central High School? Governor Orville Faubus ordered the national guard to block the admission of the black students into the school. But President Eisenhower over-rode Faubus and ordered the same national guardsmen to ensure that the federal court order was followed. Guess who won that showdown?
And a couple decades later here in Texas, Federal judge William Wayne Justice ordered the Texas TDC to build more prison cells to relieve a perceived over-crowding situation. Then-governor Bill Clements publicly proclaimed that Texas would not build more prisons and would only consider pitching army tents on the prison grounds, saying that if tents were OK for our GIs serving in WW II, they'd be OK for prisoners. Judge Justice intimated that if Gov Clements embarked on such an endeavor, he would hold the Texas governor in contempt of court. Guess who won that showdown? Texas promptly began the biggest prison building program ever seen in our state.
So....the moral of this story is that saber rattling is fine and dandy, but if the Feds want to have their way, they will prevail.