However , supporters of the presidential system question the validity of the point . They argue that if presidents were not able to command some considerable level of security in their tenures , their direct mandates would be worthless . They further counter that republics such as the United States have successfully endured war and other crises without the need to change heads of state . Supporters argue that presidents elected in a time of peace and prosperity have proven themselves perfectly capable of responding effectively to a serious crisis , largely due to their ability to make the necessary appointments to his cabinet and elsewhere in government or by creating new positions to deal with new challenges . One prominent , recent example would be the appointment of a Secretary of Homeland Security following the September 11 attacks in the United States
September 11 attacks
September 11 attacks
Presidential system