In September 1785, the Barbaulds left Palgrave for a tour of France; Rochemont's mental health had been deteriorating and he was no longer able to carry out his teaching duties. In 1787, they moved to Hampstead where Rochemont was asked to serve as the minister at what later became Rosslyn Hill Unitarian Chapel. It was here that Barbauld became close friends with Joanna Baillie, the playwright. Although no longer in charge of a school, the Barbaulds did not abandon their commitment to education; they often had one or two pupils living with them, who had been recommended by personal friends.
It was during this time, the heyday of the French Revolution, that Barbauld published her most radical political pieces. From 1787 to 1790, Charles James Fox attempted to convince the House of Commons to pass a law granting Dissenters full citizenship rights. When this bill was defeated for the third time, Barbauld wrote one of her most passionate pamphlets, An Address to the Opposers of the Repeal of the Corporation and Test Acts. Readers were shocked to discover that such a well-reasoned argument should come from a woman. In 1791, after William Wilberforce's attempt to outlaw the slave trade failed, Barbauld published her Epistle to William Wilberforce Esq. On the Rejection of the Bill for Abolishing the Slave Trade, which not only lamented the fate of the slaves but also warned of the cultural and social degeneration the British could expect if they did not abandon slavery. In 1792, she continued this theme of national responsibility in an anti-war sermon entitled Sins of Government, Sins of the Nation which argued that each individual is responsible for the actions of the nation: "We are called upon to repent of national sins, because we can help them, and because we ought to help them."