Would Starfleet even be allowed to spread all across Earth? That's like letting the garrison just outside your city take over every bar, hotel and bank by maintaining a block-by-block presence.
Sacrificing just one city apparently completely to the military is probably plenty enough.
OTOH, the Admiralty holding a secret meeting after an attack is a rather unlikely prospect. These are supposed to be the people who defend
the universe; in case of an attack, they should be dressing in their showiest uniforms and parading the streets. The civilian politicians might be shuffled to some safe house at the outskirts of Ulan Bator, where their decisions will not distract Adm. Marcus from ruling with his iron grip.