I do believe it was to improve trade with Asia :)
Explanation:
Steady employment. In a world where seasonal and itinerant labor was common, and economic upturns and downturns affected industries just as they do today, the army offers employment security that few other professions could match. Pay, food, and clothing was guaranteed.
Give me brainless, please
I wonder whether there would be also other options, but one very important aspect is the smog: the city center is where many industry-relevant things meet: the factories are all around it, transport, cars... and since it is surrounded by bad air, the air takes longer to dissipate. This is especially visible if the city is in a valley, such as Mexico city foe example.
Without a checks and balances system in place, any branch of government could <span>run amok without supervision</span>
