Answer:
According to Roman tradition, the Republic began in 509 BCE when a group of noblemen overthrew the last king of Rome. The Romans replaced the king with two consuls —rulers who had many of the same powers as the king but were elected to serve one-year terms. Each consul could veto, or reject, the actions of the other consul.
In addition of the answer that was stated, also they failed to realize the audacity and ferocity of the Nazi Party and Adolf Hitler that started a new world war and large scale of exterminations for the dream future and living space. Also they failed to stop him in his genocides and large war crimes committed during the war.
The silk road spread from the Roman empire all the way to China for trade so it helped with expansion
Judicial review is where they determine if a law is unconstitutional or not. this affected the role of the supreme court because the judicial branch aka supreme court reviews the actions of the executive and legislative branches
China had invaded Vietnam