treason
The serious crime of betraying and helping enemies of your country.
Treason is the crime of betraying your own country, especially by helping its enemies during wartime or trying to overthrow its government. It's considered one of the most serious crimes a person can commit because it threatens the safety and survival of an entire nation.
Someone who commits treason might share military secrets with an enemy country, spy for a foreign government, or join forces with invaders attacking their homeland. During the American Revolution, Benedict Arnold committed treason when he tried to hand over the fort at West Point to the British army. He had been a respected American general, which made his betrayal especially shocking.
Treason is different from simply disagreeing with your government or criticizing its leaders. In democracies like the United States, citizens have the right to protest, speak out against policies, and work to change laws they think are wrong. That's civic participation, not treason. True treason means actively working to harm or destroy your country, usually by helping its enemies in war or attempting violent overthrow of the government.
Because the accusation is so serious, the U.S. Constitution defines treason very carefully and requires strong evidence: either a confession in open court or the testimony of two witnesses to the same act. This protection exists because governments have sometimes falsely accused their critics of treason to silence them.