What happens with two internally weak countries with powerful armies?
“What happens with two internally weak countries with powerful armies?”
Ideally, nothing.
But you ask a very good question. Because it increases the chance of a terrible miscalculation.
We need to prepare to fight such a war, and prepare NOW. But, we have to be careful not to be the instigator. If, hopefully, China does not make the move the whole world expects it to make, then there is no war. We cannot start it; history will be very unkind to us if we do.
One army will lose. The one that is actually fully prepared and has been for a long time will win.