Bagley was also involved with other social justice movements. She supported the peace movement, which was developing as the Mexican–American War unfolded. She collected 146 signatures from Lowell and submitted a petition to Congress calling for an international tribunal to adjudicate disputes and therefore end the need for warfare. Bagley also supported electoral reform. In 1845, she invited Thomas Dorr to speak in the town; Dorr had previously led a group of property-less Rhode Islanders in protest against the state's voting laws, which required voters to own property. As a result of interactions with Angelique Martin, Bagley also became interested in women's rights and organised a series of lectures on the topic.
