The two major party candidates for Governor face off tonight in Cedar Rapids, but Grinnell College political science professor Barb Trish says Democrat Governor Tom Vilsack and Republican challenger Doug Gross probably won’t win lots of converts.Trish says for the most part, the candidates’ performance will just reinforce the notions viewers already have. Trish says it’s a misnomer to call tonight’s event a “debate,” as the candidates can choose not to respond to opponents, an will instead hammer out the talking points they’ve already developed.In some instances, a candidate who makes a real gaffe in a debate, or “joint appearance,” ends up damaging his or her campaign.Trish doesn’t think there’s much chance of a major goof tonight. She says these candidates face some particular challenges: Gross must convince voters he’s a potential leader and Vilsack must convince voters he’s worthy of a second term.Trish says viewers can get a sense of how the candidate responds to pressure and adversity, which she says is especially important for a challenger like Gross who has worked behind the scenes politically, but hasn’t really been in the public eye ’til this campaign.