my ISFJ mother just accepted whatever her father told her to think about politics before she married my father. However, she and my father made a deal when they got married- he would have to go to church with her every sunday and she would have to read about politics and find out what she really thought all on her own, no help from anyone else. She spent a good many years confused until she started to develop a strong interest in the politics of education and healtcare (she's an elementary school teacher) and started to develop actual political stances.
My mother now has her own political ideas (thanks to my INTP dad finding this to be a necessity!

) and yes, she is politically liberal- not an extremist, but still a definite leftist!