Anvil War

The ongoing Anvil War began on February 2nd, 2118, and is the first multi-planetary war. The planets eventually divided into one of two factions: the revolutionists and II&I. The war is at its highest point thus far, with the biggest battle of the war occurring. With over 49 million dead from both sides combined, it is projected to surpass World War 2 deaths by its end according to some people.

Prelude
Assassination of Martian President

On January 4th, 2118, the Martian President was assassinated by a terrorist organization from Earth. Panic ensued in the January Boiling as it came to be known, and eventually it came to an end with a proclamation from Mars to Earth, entitled 4 Rules,

"...

1. To allow robots and Martian officials into any and all meetings they have,

2. To allow the robots and Martian officials to vote in place of citizens from Mars, Mercury, Venus, Mars, Jupiter, Saturn, and Uranus,

3. To disallow any more incoming people from Earth to live on Mars,

4. A demand to investigate anyone they deem suspicious for conspiracy.

..."

They demanded an answer within exactly 48 hours. However, it was a state secret on Mars that they knew that Earth wasn't likely to go through with it; when consulted, a robot predicted Earth was 45% likely to go through with it.

Eventually on February 2nd, 14 hours before the deadline, Earth responded and agreed to it. By 2120, Earth had changed sides to their oppressor because of dwindling influences in elections and began to hunt anyone on Earth to head to Mars according to the 4 Rules.