In 1902, LeSueur was one of the primary organizers of the
Socialist Party of North Dakota, establishing this state affiliate of the
Socialist Party of America along with
Fargo activist Arthur Bassett and others. Speaking around the state constantly in support of the organization and the cause, LeSueur became the best known representative of the socialist movement in the state. In 1909, LeSueur was elected as an alderman from Ward 3 and later narrowly defeated Martin Jacobson with 461 votes to 424 votes to become president of Minot's city commission. In October, he attended a conference in
St. Louis with 700 other mayors to celebrate the 100th anniversary of the city. In May 1911, members of the Socialist affiliate in Minot urged LeSueur to resign as they believed that the majority of the town were unsupportive of his administration and on May 17, 1911, he and Alderman R. H. Emerson resigned. At the Socialist Party of North Dakota's state convention in February 1912, he won the party's nomination for the
third congressional district and went on to win 20.61% of the vote against incumbent
Patrick Daniel Norton's 50.74%. During
World War I, LeSueur was tapped to head the legal department of People's College, a socialist-oriented correspondence school located in
Fort Scott,
Kansas. During this time, LaSueur worked with
Eugene V. Debs, a labor leader and
Socialist Party of America candidate, who served as Chancellor of the school. During the years of
World War I the Socialist Party of North Dakota dissolved, with its adherents joining the fledgling
Nonpartisan League, headed by
Arthur C. Townley. LeSueur was active in support of this new organization. During the
1916 presidential election, he ran for the Socialist Party nomination and was the only candidate that appeared on the North Dakota ballot, but later went on to lose the nomination to
Allan L. Benson with LeSueur only taking 3,495 out of the 32,398 mail-order ballot votes. The Nonpartisan League developed financial problems in 1921, leading Townley to resign his post as president of the organization the following year. The NPL was disbanded in 1923. ==Later life==