Assembly-independent republic: Head of government (president or directory) is elected by the legislature, but is not accountable to it
Semi-presidential republic: Executive president is independent of the legislature; head of government is appointed by the president and is accountable to the legislature
Presidential system: Head of government (president) is popularly elected and independent of the legislature
Undemocratic systems:
Theocratic republic: Supreme Leader holds significant executive and legislative power
Military occupation of acquired foreign territory and the administration thereof
Martial law, temporary military rule of domestic territory
Military dictatorship, an authoritarian government controlled by a military and its political designees, called a military junta when done extralegally
Military junta, a government led by a committee of military leaders.
Stratocracy, a government traditionally or constitutionally run by a military.