I've encountered a bug/glitch or something in the 1.21 greenbelts campaign where I'm a lieutenant (8 squad members) but no AI will join it. It first started on Black Gold Estuary and every mission after that has had it. I've managed to make it to Frozen Canyon (Final Mission II) with no squad support, but now winning it's practically impossible. I've made sure that my squad count is at the max (Page Up all the way) and I've made it go all the way down (Page Down all the way) and back up just to make sure.

Have you read this article: http://runningwithrifles.gamepedia.com/Squad_control ?

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"Ad cogitandum et agendum homo natus es"

I work quickly, cheaply and qualitatively. You can choose only two of the three options.

*facepalm* Apparently I hit the "home" or "end" button. Hit it a couple more times and it worked. Thanks.