What you describe is the least effective army that can be assembled. Not saying they wouldn't try, mind you... But that's not a group you give guns and put into a battlefield.
Am Californian, would seriously consider joining Canada.
Trump could reflexively say whatever (as he does) but so much cargo comes through here his business people wouldn't let him do it. Too much of a tariff risk.
His uninformed voters buy it.
It's that simple. That and Trump is used to bullying.