When and if a leftist Democrat federal government issues orders for any federal government organ to seize citizen firearms, there WILL be war. This is "the" thing that the left most dearly wants...an unarmed populace. Elected or no, this IS a clear violation of the Constitution. "IF" the military chooses to participate in such action, legally voted or not, "I" would certainly consider them to be acting on illegal orders, and would aim accordingly.
Addendum....if Hillary had been elected, I believe that the “disarmament agenda” would have been a high priority.
Pure fantasy, unless you refer to cities like Chicago today.
Democrat-run Chicago already has the nation's strictest gun laws but five-times the national average murder rate.
As a result many thousands of illegal guns are seized each year and thousands arrested for illegal possession.
Is that a "civil war"?
Some have even called for the United Nations to intervene in Chicago and President Trump long ago offered Federal help to Democrat Mayor Emanuel, not accepted so far as I know.
Result: Chicago has five times the national average murder rate and, where nationally crime trends down, in Chicago it only gets worse.
Is that then the CWII you imagine, and if so, which side are you on?