Five candidates are preparing for the CNN debate to be held in Las Vegas on 13 October 2015: Hillary Clinton and Bernie Sanders, but also Martin O’Malley, Jim Webb and Lincoln Chafee. There are two likely outcomes.

The first is an opportunity to actually debate the issues. The previous Fox and CNN debates failed to engage the candidates in a genuine debate of the issues, perhaps as a consequence of the sheer number of candidates on stage. On Tuesday, with five candidates, there will be no excuse for not asking the candidates to debate key issues, yet that remains to be seen. [Tracy Westen and I have been writing about this shortcoming of the GOP debates.]

Secondly, I expect that this is a key opportunity for the lesser known candidates to gain greater visibility. Martin O’Malley, for example, could gain support for his candidacy by virtue of just being heard. Even though there are fewer candidates in the Democratic Party Primary, it is amazing how focused the media have been on the two frontrunners, Hillary Rodham Clinton and Bernie Sanders. Even Joe Biden, yet to decide on his candidacy, has received tremendous coverage. The other three candidates have received very little indeed. For example, the Sunday NYT (11 October 2015) prepares readers for the coming debate by discussing the debating skills of Bernie and Hillary, but not one column inch on O’Malley, Webb, or Chafee. This is one more illustration of the limitations of the mass media in elections. More use needs to be made of the Internet, Web and social media to cover a wider range of issues and candidates.

It might well be that the three lesser knowns will have the most to win in this CNN debate, as this stage will give them the best opportunity to-date to make their case as credible alternatives to the two front-runners. My prediction is that Martin O’Malley will be the biggest winner of Tuesday’s CNN debate, but the most important outcome should be the airing of candidate positions on key issues. This is the responsibility of the moderators at CNN.