Low. In fact, I wouldn't be surprised if the E.U. already has secret plans drafted, with consultation with China, to divide up the United States. If a war came here, our soft general public who has never had to fight off an enemy on our own mainland soil for generations will sit by watching in shock. I can even picture prominent Dems scheming to get gubernatorial appointments from the ChiComs, and the N.Y. Times writing glowing editorials of "the ChiCom freedom fighters coming to bring us our glorious revolution." *cough*
I would fight to the death if it ever came to that. But you have a point. There is 47% of us who would not fight off an invasion if it ever came to it.