It's basically an act of war, you are destroying their self-governance. So when war is moral (ie in defense of self or others against violent oppression / other

It's basically an act of war, you are destroying their self-governance. So when war is moral (ie in defense of self or others against violent oppression / other autonomy destroying acts), there is a case to be made. But then you still need to justify your specific means - which is a direct attack on the Civilians of the country by taking away their apparent liberty without telling them that is the case. Obviously that view entails understanding lies as taking away others' liberty by denial of truth on which to base their decisions. The decision would be easier (but not easy) to make if their own government was deceiving them grossly, in which case your interference could bring more truth than it obscured. Any moral choice remains predicated on the lack of availability of better, more direct and honest methods. And of course these are practical decisions with all the obscurity and uncertainty they entail. Between the characteristic of an attack on civilians and the potential of actually bringing in more truth than is obscured if their own government is sowing lies, I first pointed to helping the citizens of the country as the only moral option. Without making a decision (I would have to think about it further), there might be drastic circumstances where there was no other viable course of action - but again within the context of acts of war and significant collateral damage.