Whether or not the debate between Donald Trump and Bernie Sanders materializes, the mere possibility of such an event merits our consideration. Apart from making history, what would a Trump-Sanders face-off mean for the three principal stakeholders?
TRUMP: For Trump there is perhaps more risk than he realizes, given the inherent volatility of live debates. Although Trump has great familiarity with live TV, he has little familiarity with a format that would pit him one-on-one against a challenger who is raring to match wits. Trump's "Triumph the insult comic dog" shtick plays best either in small doses or when it comes packaged as part of a solo act. With an unintimidated rival onstage, one adept at hammering home an argument, the locker room towel-snapping is likely to wear thin.
When it comes to debates, Trump's opponents have been waging war on the wrong battlefield: instead of approaching Donald Trump as a political phenomenon, they should approach him as a show business phenomenon. The challenge for Sanders, and Hillary Clinton in the fall, is to diminish Trump not as a politician but as an entertainer. This is, of course, easier said than done, but as a general goal his competitors must figure out a way to make Trump's act wear thin, to render him not just boorish but boring--someone the nation would be loath to watch every day for the next four (or eight) years. The live debate environment is an enormous gift for Trump's rivals to exploit, because the long-form format requires participants to engage in detailed discussion on live TV, in a milieu in which knowledge cannot be faked. Furthermore, Trump is exceptionally vulnerable to ridicule--opponents should take a cue from how Barack Obama rose to the occasion at the 2011 White House correspondents' dinner.
Naturally there is the prospect that Trump could win a TV debate with Bernie Sanders--or with Hillary Clinton, for that matter--by sheer force of personality. But the Democrats, like the Republicans before them, cannot hope to prevail if they misapprehend the fundamental nature of the game. Debates are television shows against a political backdrop more than they are political events against a television backdrop--this is something Trump instinctively gets, far more than his competitors do.
SANDERS: As Sanders approaches the end of the primary season, anything that puts him front and center can be viewed as a plus. But if a debate with Trump does not occur before the vote in California, the concept offers no political gain. Even if Sanders wiped the floor with Trump, Sanders would continue to face insurmountable mathematical odds in securing the nomination.
In a debate against Trump Sanders holds several advantages. First, unlike Jeb Bush, Marco Rubio and the like, Sanders is not afraid of Donald Trump. It takes a New Yorker to outtalk a New Yorker, which would make this perhaps the loudest presidential debate ever staged. Second, Sanders brings a record of personal integrity that affords a striking contrast to the Republican nominee. Third, as a billionaire (maybe), Trump presents Sanders with the perfect foil, a literal embodiment of capitalist greed standing just steps away. What debater wouldn't kill for that?
On the other hand, Sanders has been only sporadically effective in his debates with Hillary Clinton. As a performer, he operates within a more limited range than Trump, and he lacks his rival's innate sense of drama. As for Sanders' disinclination to personally attack, this could cut a couple of ways: it could wind up heightening Trump's rudeness and making Sanders the more sympathetic figure, or it could make Sanders easy prey for the Donald's crocodile jaws.
CLINTON: Let me defy conventional wisdom and advance the case that Hillary Clinton could be the true beneficiary of a Trump-Sanders match. Beltway pundits make the point that a debate would siphon attention away from Clinton at a critical juncture in the campaign. But a few days out of the spotlight might not be such a bad thing for a candidate who runs the risk of overexposure. If it's true that voters dislike Clinton the more visible she becomes, then why not ration her appearances more judiciously?
Furthermore, any damage Sanders might inflict on Trump would ultimately accrue to the Democratic nominee--which is to say, Hillary Clinton. A live bashing of Donald Trump before tens of millions of viewers would soften him up for Clinton in the fall, not to mention giving her an invaluable road map for debate prep. Trump has never done a one-on-one debate, so we don't yet know whether he is likelier to emerge as a dragon-slayer or as Frank Morgan behind the curtain at Oz. If Trump-Sanders happens, Hillary Clinton gets a free lesson in how to prepare for her own moment in the ring against a highly unpredictable opponent.