Trump-Sanders debate would be Hillary Clinton's worst nightmare

Just when you thought the 2016 election was starting to get a little predictable, a big wrench has been thrown into the works.

A Donald Trump vs. Bernie Sanders debate in the coming days before the June 7th California primary is getting closer to becoming a reality. If this happens, it will likely be a huge boost for Sanders, a mild aid to Trump, and -- to borrow the key buzz word of this election so far – a YUGE pain in the neck for Hillary Clinton.

For Sanders, this entire election has been a "nothing to lose" proposition. He was given no chance to even make a dent in Mrs. Clinton's inevitable coronation, er presidential nomination, by the Democrats. And as a lifetime Senate backbencher, he was not in danger of losing a chairmanship or leadership position. While it's basically impossible for Sanders to overtake Clinton in the delegate battle, the latest PPIC poll shows Sanders trails her by just two percentage points among likely California primary voters.

Republican presidential candidate Donald Trump (l) and Democratic presidential candidates Hillary Clinton and Bernie Sanders (c, r).
Getty Images
Republican presidential candidate Donald Trump (l) and Democratic presidential candidates Hillary Clinton and Bernie Sanders (c, r).

Needless to say, if Sanders wins this primary it will wound Mrs. Clinton greatly. And Sanders chances to do just that would rise if this debate comes off. The contest would no doubt be the most-watched event in Sanders' political life and Clinton wouldn't even be there to defend herself. For a campaign that's been suffering a number of failures lately, its refusal to debate Sanders and setting off this alternative contest vs. Trump is perhaps the biggest failure yet. She can't even benefit from a sympathy factor if Trump and Sanders get too nasty in attacking her in absentia, because her absence is entirely her own fault.

It's also not wise for Clinton to allow any major campaign event to occur without her participation. With many right wing and progressive voters still hoping she may be disqualified from the race if she is indicted over her State Department email scandal, this kind of "Clinton-less" event gives them a taste of what they've been praying for all year.

The only potential negative for Sanders is he's wading into waters vs. Trump that he's not quite used to. His battle with the Clinton campaign has become nastier of late, but it's nothing compared to what Donald Trump's opponents have had to face over the past 10 months. Sanders can get pretty nasty himself, as many of his Senate colleagues can tell you, but even though he can fight fire with fire against Trump it doesn't mean that's the kind of image he wants to present to undecided voters in California and nationwide.

If the debate gets so nasty that it becomes an embarrassment on the level of some of the GOP debates earlier this year, the Clinton campaign could possibly get some traction by claiming it was staying above an unnecessary nasty fray all along. Sanders, by contrast, could come off looking like the Democratic Party home wrecker the Clinton forces have been portraying him to be for last month. But Mrs. Clinton and establishment Democrats and Republicans have been acutely tone deaf about the new and rising tolerance the voters have had for nastiness in this new social media dominated world. It goes with the territory.

So what's in this for Trump? He already has the California primary sewn up, and he seems to be getting into a groove attacking Clinton. At the same time, he's been sending almost daily encouragement to Sanders' camp with comments about how the Democratic Party primary process is rigged against him. So why would Trump seemingly take his eye off the Clinton ball and simultaneously risk angering even the few Sanders voters who could potentially switch over to him or just stay home in the general election?

The answer is the exposure will be worth it, even for the overexposed Trump. Right now, Trump's #1 best goal is to prove to as many people as possible that he's not crazy. And a relatively cordial, yet lively, debate vs. fellow firebrand Sanders would go a long way toward accomplishing that goal. And each and every moment Trump and Sanders seem to be on the same page about Hillary Clinton's record or choreographed path to the Democratic nomination will be extremely helpful to the Trump camp. Trump's winning image as an outsider can only be enhanced by a sustained national TV appearance with fellow outsider Sanders.

The only unanswered question is how the Clinton camp will be able to stay out of this debate as the publicity and excitement over it grows. "The best thing Clinton campaign Chairman John Podesta could do is call everyone's bluff and get Hillary to show up to the debate after all, eliminating Trump from the podium. But the Clinton campaign has been about predictability for years now and no matter how disastrous the outcome, it's desperately sticking to the script.

Commentary by Jake Novak, supervising producer of " Power Lunch ." Follow him on Twitter @jakejakeny .

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