When Democratic Gov. Mark Dayton and Republican challenger Jeff Johnson take the debate stage on Sunday, the Independence Party’s Hannah Nicollet won’t be there.

Neither will gubernatorial candidates from the Libertarian or Grassroots-Legalize Cannabis parties.

The debate, hosted on the St. Paul campus of Hamline University by FOX9 television, will be limited to the frontrunners from the two leading parties.

The format isn’t unusual this season — with Sunday’s match-up at Hamline, Nicollet has been included in two of the four gubernatorial debates to date — but it has drawn pushback from the excluded parties.

Nicollet, Libertarian candidate Chris Holbrook and Legalize Cannabis candidate Chris Wright are expected to host a joint press conference at 8 a.m. Sunday protesting their exclusion.

Their media event will be held on the Hamline campus along Hewitt Avenue, an hour before Dayton and Johnson are scheduled to spar at the university’s Klas Center on Taylor Avenue.

A recent gubernatorial debate at the Duluth Playhouse marked the first time in more than a decade that the Independence Party had been excluded from the debate stage.

“In Minnesota, they’ve usually been included,” said Andy Burns, executive director of the Libertarian Party.

The struggles of the Independence Party this year have been well chronicled. Nicollet failed to draw enough donations of $50 or more to qualify for public campaign subsidy by the July deadline. And the party’s 2010 gubernatorial candidate, Tom Horner, broke ranks last month and endorsed Johnson for governor.

In a note on its Facebook page titled “Minnesota Calls Shenanigans!,”

the Independence Party noted that favoring a political candidate could

imperil a nonprofit university’s federal tax-exempt status.

Hamline University officials say they did not choose who will appear on stage Sunday.

“To clarify Hamline’s role in this event, the editorial decisions, such as which candidates would appear at this event, are entirely those of FOX9,” said JacQui Getty, a university spokeswoman.

“Hamline was approached as a partner venue to provide a site for this event, and FOX9 is renting that space from the university,” Getty said. “Hamline does not support or oppose candidates for public office.”

In a statement Saturday, the Libertarian Party of Minnesota called the decision to exclude all but the frontrunners “a stunning show of partisan favoritism.”

Frederick Melo can be reached at 651-228-2172. Follow him at twitter.com/FrederickMelo.