Filing closed for the Montana primaries (both presidential and for other office) on March 20. Montana has four ballot-qualified parties: Republican, Democratic, Constitution, and Libertarian.

In the Republican presidential primary, John McCain and Ron Paul are the only candidates. In the Democratic primary, unsurprisingly, the two listed candidates are Barack Obama and Hillary Clinton. Neither the Libertarian nor the Constitution Parties chose to have presidential primaries.

In the primaries for other office, the Constitution Party has nine legislative candidates, and a candidate for Secretary of State. The Libertarian Party has candidates for U.S. House, Governor, and two legislative candidates.

The Constitution Party currently holds a state house seat, but its legislator, Rick Jore, cannot run for re-election because of term limits. The Constitution Party has no candidate in that district (the 12th district). However, Ronald Marquardt, who had run as the Constitution Party nominee for Clerk of the State Supreme Court in 2006, is running in the Republican primary for the 12th House district. Two other Republicans are also running for the Jore seat.

The Green Party petition for party status failed.

In 2007 the Montana legislature moved the non-presidential independent candidate deadline from June to March. No independent candidates for statewide office, nor for State Senate qualified by the new March deadline, but two independents for State House qualified.

It is likely that an independent candidate will soon file a lawsuit against the new March petition deadline for non-presidential independents.