[1][2] According to her official biography, Theresa Manzella was formerly employed at Pontiac Motors headquarters and from 1985 to 1990 as a supervisor at Electronic Data Systems.
In the Republican primary, she faced fellow representative Nancy Ballance, with Manzella reported to be the more conservative of two candidates.
[6][7] In the 2019 Montana Legislature, Manzella sponsored a bill (HB 575) that would have eliminated almost all childhood vaccine requirements for day care centers for those who claimed a religious objection.
[8] In a 2018 post on the Ravalli County Republicans' Facebook group, Manzella claimed that the local schoolteachers' union, MEA-MFT, was, "working against our constitution and for socialism and communism.
[9] State Senate candidate Jason Ellsworth, a fellow Republican, also criticized Manzella's remarks.