Treason

"...treason is the crime that covers some of the more serious acts of betrayal
of one's sovereign or nation.

A person who commits treason is known in law as a traitor.

Oran's Dictionary of the Law (1983) defines treason as
"...[a]...citizen's actions to help a foreign government overthrow, make war against,
 or seriously injure the [parent nation]."

In many nations, it is also often considered treason
to attempt or conspire to overthrow the government,
even if no foreign country is aided or involved by such an endeavour.

...the word "traitor" may also be used to describe a person
who betrays...their own political party, nation, family, friends, ethnic group,
team, religion, social class, or other group to which they may belong.

...the term "traitor" is used in heated political discussion
– typically as a slur against...officials in power
who are perceived as failing to act in the best interest of their constituents."

Wikipedia