After the Republicans and Democrats finished their conventions in late July, the Green Party gathered Aug. 6 to nominate Dr. Jill Stein for the presidency. Stein’s campaign — with her party on ballot lines in the majority of states — could be a breakthrough bid for the Greens, and for multiparty democracy.

The key word, of course, is “could.” To make this breakthrough, supporters of the Green nominee, as well as progressives who will be inclined to back Democrat Hillary Clinton in order to block the candidacy of Republican Donald Trump, should advocate for something that is rare in presidential politics: fair play.

Stein is not just up against the Democratic and Republican nominees. She is up against a rigid two-party system that erects high barriers to those who seek to open up the process.

But Stein’s approach, and the year in which she is running, make it possible to imagine that at least some of the barriers could be knocked down.