Montana requires all qualified parties to nominate by primary. According to this story, both candidates in the upcoming Green Party U.S. Senate primary are really acting on behalf of one of the two major parties. Dennis Daneke, one of the two candidates, says if he wins the primary, afterwards he will withdraw, because he supports the Democratic Party and doesn’t want a Green candidate on the general election ballot for U.S. Senate. The other Green primary candidate for U.S. Senate, by implication, is running because in her heart she favors the Republican Party, and she wants a Green on the November ballot.
The Green Party says neither candidate is a bona fide Green. If the state allowed small qualified parties to nominate by convention, then the Green Party would have control over whether or not it wants to run someone for U.S. Senate. A convention is always free to decide to run no one for a particular office. This is one more example of why mandatory primaries for small qualified parties are a bad idea.