Adultery and/or cheating on a significant other.
After seeing him kiss another woman, Shannon accused her husband of sexual treason.
The influential American Jewry's agreement to trick the US populace into WWI in exchange for Britain giving Palestine to the Zionists (Balfour Declaration). This resulted in the destruction of Germany and WWII.
The Big Treason shaped the modern world more than any other event of the last 150 years.
Giving your friend less than $200 for his wedding.
Man, if you give anything less than $200, then that's fuckin treason man.
When a sporting team beats your sporting team and you accept it and move on rather than make unlimited ridiculous excuses why you should've won.
Person 1: They beat us fair and square, they were better on the day
Person 2: That's treason!
Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort.
Maybe the SCROTUS should learn what treason is.