It really wouldn't take much to start a civil war, of sorts. Federal agents go to arrest a group of people for NFA violations, and Montana citizens - police, unorganized militia, whatever - get really PO'd and stop them before they leave the state. Or, a Federal agent or two (and maybe a silencer owner) gets shot during a secret arrest, and the local populace gets angry. Lots of things.
and
I do not think that I would want to volunteer for that detail. Me thinks it might be, not so much fun.
The detail would suck but it probably wouldn't wind up as a civil war. There
are plenty of places throughout Russia and states of the FSU where the
authorities maintain very little control. Moscow still sends in their interior
enforcers, there are gun battles, people get killed, and the infrastructure
(what there is of it) is third world. In the US enforcement would all depend
on the "big picture." If DC feared a Montana split would open the flood-gates,
then they would intervene. If a Montana split went largely unnoticed in the
rest of the US, probably very little would be done. Which do you think is
more likely?
BTW, speaking on US city-states-unto-themselves:
http://news.yahoo.com/s/nm/20070110/pl_nm/california_schwarzenegger_dc
"We are the modern equivalent of the ancient city-states of Athens and Sparta. California has the ideas of Athens and the power of Sparta," Schwarzenegger, who played Hercules in his first film role, told legislators at the capitol. "Not only can we lead California into the future ... we can show the nation and the world how to get there."
"We can do this because we have the economic strength, the population, the technological force of a nation-state," he said in the address that sets out his annual agenda.
You have to remember as long as the local king collects taxes from his
resident serfs, and pays them in fealty to the Emperor, then the local
king actually has a wide amount of leeway in his local rule.
One should consider the history of Judea in the Roman Empire. When they
paid taxes and did not resist the legions, things went fine --often prospered
for the common person under Herod (BTW, not a nice guy). When the common
person joined a revolt, taxes were no longer sent to Rome and some group
took control of Jerusalem and declared independence, things didn't go so well.
With history as a guide as long as the citizens of Montana
pay taxes, the
governor pays appropriate lip service (called
homage in ye olde days) to DC,
and some armed group doesn't take control of Helena and make a declaration
on CNN, this bill if/when becomes law may have little impact.