In 1910, he ran for state treasurer against incumbent Republican Gunder Olson and in September was named as vice chairman of the state Democratic party, but was defeated. Following the resignation of former Commission President Arthur LeSueur on May 17, 1911, a special election was held on June 6, in which Halvorson narrowly defeated Dorr H. Carroll and Peter Vandenoever with 232 votes against 196 and 94 votes. In 1912, 1914, and 1918, Halvorson ran for North Dakota's third House district, but lost each time with his best showing being 31.16%. He served as a delegate to the 1916 Democratic National Convention and gave his support to incumbent President Woodrow Wilson.