Alright, I've started a new game as Red, with the balancing mod. Now, I'm being besieged in Moscow (by one anarchist unit), Tsaritsyn, Simbirsk, Ekaterinodar and Aralsk. I estimate that my forces in Moscow, Tsaritsyn and Aralsk are strong enough to win a straight up battle, so I'm trying to get them to actually attack the enemy.
In two turns in a row, now, I have tried issuing the sortie order, while setting them on offensive/defend, but it doesn't seem to be working. They just sit there, doing nothing. In Moscow, the situation is particularly bizarre, since Trotsky is leading a stack of 10,000+ crack troops, while the enemy consists of one anarchist unit, and now I've lost control of the region.
So how do I make my guys sortie? I'm pretty sure I've done it before, so I have absolutely no idea why it isn't working now.