1918 United States Senate election in Montana

1918 United States Senate election in Montana
	County results
U.S. senator before election; Thomas J. Walsh; Democratic	Elected U.S. Senator ; Thomas J. Walsh; Democratic

The 1918 United States Senate election in Montana took place on November 5, 1918. Incumbent United States Senator Thomas J. Walsh, who was first elected to the Senate in 1912, ran for re-election. He won the Democratic primary uncontested, and was opposed in the general election by Oscar M. Lanstrum, a former State Representative and the Republican nominee, and Jeannette Rankin, one of two United States representatives from Montana's at-large congressional district and the nominee of the National Party. Walsh narrowly won his second term in the Senate.

Democratic primary

Democratic Party primary results^[1]
Party		Candidate	Votes	%
	Democratic	Thomas J. Walsh (incumbent)	28,553	100.00%
Total votes			28,553	100.00%

Oscar M. Lanstrum, former State Representative
Jeannette Rankin, one of two Congressional representatives from Montana's at-large congressional district
Harry H. Parsons, attorney
Edmund Nichols

Republican Primary results^[1]
Party		Candidate	Votes	%
	Republican	Oscar M. Lanstrum	18,805	41.59%
	Republican	Jeannette Rankin	17,091	37.80%
	Republican	Harry H. Parsons	5,878	13.00%
	Republican	Edmund Nichols	3,443	7.61%
Total votes			45,217	100.00%

1918 United States Senate election in Montana^[2]
Party		Candidate	Votes	%	±%
	Democratic	Thomas J. Walsh (incumbent)	46,160	41.07%	-0.10%
	Republican	Oscar M. Lanstrum	40,229	35.79%	+9.06%
	National	Jeannette Rankin	26,013	23.14%
Majority			5,931	5.28%	-3.79%
Turnout			112,402
	Democratic hold		Swing