Why did Montezuma II go to war with surrounding city-states

Montezuma II was the last ruler of the Aztecs in the years between 1502 and 1520, when the Spaniards conquered the empire.

During the reign of Montezuma, the Aztec Empire reached its peak of geographical size. Montezuma invaded its neighboring nations and expanded its empire all the way south to Soconusco (a territory that now borders Mexico and Guatemala). During this war, the Zapoteca and Tlapaneka nations were incorporated into the Aztec Empire, always with the aim of obtaining greater benefits through the payment of taxes and tributes by the conquered territories, but also with the aim of obtaining new prisoners to offer as sacrifice to their gods.

gaius cassius longinus and marcus junius brutus, former enemies of julius caesar who'd joined the roman senate, led caesar's assassination, dubbing themselves "the liberators." and the second one is   the assassination of julius caesar was the result of a conspiracy by many roman senators led by gaius cassius longinus, decimus junius brutus albinus, and marcus junius brutus. they stabbed caesar (23 times) to death in a location adjacent to the theatre of pompey on the ides of march 15 march 44 bc.

it was certainly a debatable decision, mainly because it was based primarily on political - and not on legal or social - views. since the congress at that time was led by members of the republican party, and the territory that the tribes wanted to turn into an exclusively indian state was predominantly democratic, the proposal (as expressed in the constitution) did not succeed, but the constitution itself proved to be of crucial importance in the creation of the state of oklahoma, and, most importantly, it guaranteed the involvement of representatives of the indian tribes in the government of the future joint state.  

as a member of congress, i would have voted to ratify the constitution, or at least to have it tabled. ignoring it was an interested and partial decision.