To save those cities you have to send your loyal units into MILGOV controlled areas, At best you work together to repel the Mexican forces and gain a little respect (MILGOV will get more as they have more forces). At worst you lose the forces to MILGOV control as they realize they can get better logistical support from MILGOV. So to CIVGOV not losing the units to MILGOV might be seen as a "win". Then it comes down to how to use this "resource" to your best political advantage.
So while illogical it can be seen as a high risk high reward scenario to deploy overseas. I still feel it is stupid at every level, but these are politicians we are talking about
