I think the answer is no, the militia will replenish slowly on its own, but you have no control over it. (Maybe your support for militia has an impact, but I am not certain.)
Not sure whether you are satirizing the purchase process or the game itself, but this strikes a chord, in either case. :)
I am wavering between raving about the vast potential of this game and rage quitting over the way that doing routine things is made nigh impossible. I gave up for the night when building a new truck station failed to solve the logistical problems surrounding the city in my newly acquired zone, but woke up to find that DasTactic had put up three videos on solving this sort of problem. Just the fact that it requires three videos to explain road systems/logistics tells you what sort of game it is. I have other things to do this morning, but I watched enough to realize that there are relevant screens strewn here and there around the interface, none of which I would have been likely to discover on my own. So much, “be in this mode, then click here, then a button will appear there, and a panel will show up which does not look interactive but is.” Hyperbole, but not by that far.