It has actually been serious for quite some time. That dog-whistling is all about convincing themselves that they could actually win such a conflict - because wars generally don't get started until that belief (mistaken or well-founded, it doesn't matter) is widespread.
For now, my situation awareness is cranked up to "James Mattis" level:
“Be polite, be professional, but have a plan to kill everybody you meet.”
That’s a great quote.
BTW, their attitude (as well as the attitude of many on the right) reminds me of that dinner party scene in the early part of “Gone With The Wind”, where all those southern gentlemen were excited to go to war to “kick those Yankees’ butts”.
It also hints at the validity of the Ronald Reagan line, “No country was ever attacked because they were too powerful to defeat.”