Encouraged by another of the Vermont immigrant community,
Paul Holland Knowlton, Foster stood for election to the
Legislative Assembly of Lower Canada in the general elections of 1834. He campaigned as a supporter of the Governor General, but was defeated. Foster's friend Knowlton had been appointed to the new Legislative Council, and he again encouraged Foster to stand for election, as a supporter of the Governor General,
Lord Sydenham. This time, Foster was elected to represent
Shefford in the Legislative Assembly. In the first session of the Legislative Assembly, the major issue was the union of the Canadas. Opponents of the union introduced a motion condemning the way the union had been imposed on the people of Lower Canada. Foster voted in favour of the union and against the motion, which was defeated. During the session, Foster was a consistent supporter of Lord Sydenham and his government, and opposed to the reform program of the Upper Canada reformers and the
French-Canadian Group. Foster was re-elected in 1844. He continued to be a member of the "British Tory" group from Lower Canada, supporting the Governor and opposed to the reformers. Although he consistently supported the governor, Foster did not take a major role in the Assembly. In the general election of 1848, he was defeated by a reform candidate,
Lewis Thomas Drummond. Foster was actually glad to return to his medical practice and took no further part in politics. == Later life and death ==