system
Given the following post, respond as if you're commenting on Reddit:
human
[Mother 1+2/Earthbound] Why hasn't the military gotten involved?

In both games, there are war veterans, showing that a military does exist. (In 2, one of the NPCs at the Twoson bus station claims to be a war veteran.)

In both games, conventional military-type weapons are shown to be far from useless against even Giygas' more advanced minions.

In both games, while the public may not know everything that's going on, there are some clear signs that the country is facing some kind of paranormal threat. People talk about the abductions and the zombies at least.

So why haven't the authorities responded in any way?
gpt
For starters, Giygas had already influenced the entire Onett police force.  Giygas is also in control of the powerful people in Fourside, and the officers there admit that they work directly for Montolli, who is (in a bit of a roundabout way) under Giygas' influence.

And you do encounter soldiers, most likely having gone rogue, selling weaponry and explosives used in the fight against Giygas.  They don't seem to know what they're fighting, but they are helping the good guys and are seemingly aware that they're supporting the fight against *something.*

For the rest of the various armed forces, remember that almost nobody knows who or what Giygas even is.  Many people aren't aware that there's even a fight brewing, because 199X is still 10 years before the fight against Giygas even happens.  At this point, Giygas' influence is only beginning to spread and create what will become his army.

As is shown, many people fall to Giygas' influence by default until being met and sometimes "freed" by Ness' influence.  If the militaries are involved at all, they are likely influenced to be complacent and unhelpful, the example of the Onett police being the clearest analog to use for comparison.

Additionally, as is seen in Mother 3, the only military shown in the series is >!already under Giygas' influence, in that they're under the influence of somebody who had been directly influenced by Giygas.!<  Though this is long after M1 and M2, there's not much reason to believe that other Eagleland militaries would have fared much better, though they would have probably taken longer to corrupt.