How did the united states acquire hawaii? was the action constitutional?

Hawaii was acquired by the United States through annexation. It was an illegal overthrow led by Caucasian businessmen many of whom were citizens of the kingdom of Hawaii supported by the US government. Queen Liliuokalani did not want to risk loss of life so she did not fight the overthrow.

It was acquired by annexation (taking over) an illegal. act the queen did not want to lose lives of her people so she did not fight back 
and i am pretty sure it was not constitutional.