2018 North Korea vs 1918 United States

North Korea falls through a wormhole and is sent back in time 100 years. Kim Jong-un finds himself in December 1918, just after World War I ended -- and facing a much weaker United States. He immediately declares war.

• R1: North Korea invades the Philippines.
• R2: North Korea invades Hawaii.
• R3: The US invades NK.

North Korea is in the same location you'd expect it to be. Really, Imperial Japan should be ruling over the Koreas in 1918, but let's say they and the rest of the world ignore what's happening.

Nukes absolutely allowed.