After Ali, the last caliph of the Rashidun, was murdered, the Umayyads came to power by:

The Rashidun Caliphate was the first of the four major caliphates established after the death of the Islamic prophet Muhammad. It was ruled by the first five successive caliphs (successors) of Muhammad after his death in 632 CE (AH 11).

Rashidun

Explanation:

The time period under the leadership of the Four Caliphs is called the Rashidun Caliphate by historians. The Rashidun Caliphate lasted for 30 years from 632 CE to 661 CE. It was followed by the Umayyad Caliphate. The city of Medina served as the first capital of the Caliphate.

it was the "4. potsdam" conference that demanded the unconditional surrender of japan, since it was clear that the japanese would continue to find until the very last man otherwise.