Throughout U.S. history, no party other than the Democratic and Republican Parties has ever polled as many as 1,500,000 votes for its nominees for the office at the top of the ballot (in the entire U.S.) in a midterm year.
The only instances in which a party, other than the Democratic and Republican Parties, has ever polled as many as 1,000,000 votes for its top-of-the-ballot nominees in a midterm year are: (1) Peoples Party 1894, 1,312,017; (2) Progressive Party 1914, 1,489,151; (3) Reform Party 1998, 1,407,005; (4) Libertarian Party 2002, 1,100,246; (5) Libertarian Party 2010, 1,015,009.
This year, it seems extremely likely that the Libertarian nominees for the office at the top of the ballot will poll over 2,000,000 votes. This is partly because the Libertarians have more candidates for the top-of-the-ticket office this year than ever before, but mostly because so many of the party’s nominees are receiving substantial support.
“Office at the top of the ticket” is deemed to be Governor, for all the states that elect Governors this year. For those states that don’t elect Governors this year, it is deemed to be U.S. Senate. For the handful of places that have neither gubernatorial nor U.S. Senate races this year, the offices are: District of Columbia Mayor; Indiana Secretary of State; Missouri Auditor; North Dakota Secretary of State; Utah Attorney General; Washington U.S. House.
The Libertarian Party has candidates on the ballot for the topmost office in 36 states, the most it has ever had (this treats the District of Columbia as if it were a state). The previous high for the party was 2002, when it had candidates for that office in 34 states. The Reform Party in 1998 only had nominees for the topmost office in 18 states, but it got a very high national vote because of its showing in Minnesota and New York. The Progressive Party in 1914 had such nominees in 38 states. The Peoples Party in 1892 had them in 44 states. For purposes of this calculation, organized territories are treated as “states” because they elected Delegates to the U.S. House, and that office has been included as the office at the top of the ballot.