Hereunder (in a point form) are the few things that undermine political legitimacy of any Goverment:
1.Giving unfulfilled promises to citizens every now and then.
2.Assuming Citizens don't know of any embezzlement (If any) by Government leaders/officials.
4.Unequal distribution of National wealth in a particular State or Nation.
5.Cutting benefits that affect Citizens i.e Health Service,Housing,Education etc
6.Using public office as a family business enterprise where the whole favour goes to the Family & Family friends.
7.Do not listen to citizens of any concern assuming the complaints are not basic
8.Making the constitution that favour the rulling system for example lifetime president (including those serving for a long time as if they are the only best leaders to cling on power as per their wish)
10.Poor social services i.e Health,Education etc.