Season 7 Why didn't Buffy ask the Military (or at least Riley) for help against the First?

When Buffy and the gang are gathering the potential Slayers and are needing as much help against the First as possible, why didn't they ask the military for help? It's not like they couldn't.

Willow had a direct email to Riley's wife and they even got an entire squad to help get the chip out of Spike with one phone call?

Even if the Military was not willing Z(which would make no sense since it's gonna be the end of the world and all.) But Riley at least would come help Buffy even if he is not in love with her anymore.

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What annoys me most is that it's not even mentioned on why it's not an option.