They may think that, but it'll never happen. You can't just make that level of logistical change over night. Canada could maybe help, but they also have the most to lose out of any foreign nation that might aid the Blue Side, since they are within Freedom distance.
I wish people would stop with the drone strike meme, the US has spent the better part of the last two decades proving that you can't drone strike people into submission. It doesn't work on sub-100 IQ populations with grandpa's AK-47, it's sure as shit not going to work on most Red State Americans or Rural populations. And if they just start bombing random farmhouses, the rest of the world will quietly start distancing themselves from that. Noodly armed small souled soyboy bugmen are not going to be capable of going out into the rural red state areas and taking and holding them. Go ahead, send the Grand Army of the Blue States into, I don't know, the logistical nightmare of Appalachia. Have them bravely try to roll up on rural, great plains ranches and farmsteads against people who've been hunting all their lives and regularly bag animals at hundreds of yards. They'll have enough problems keeping their cities from burning down from the inside.
We're talking about people who have wailing meltdowns from the recoil of an AR-15. I mean, never underestimate your enemy and all, but lets not pretend we're talking about superhuman Socialist New Men here.