Hillary Clinton blew it with that convention speech

Hillary Clinton did not make any major gaffes or glaring mistakes in her big speech to close the Democratic National Convention Thursday night. But by playing it extremely safe and leaving the nation with really only one clear message from the address — Donald Trump is bad — she has left the door wide open for Trump to win the election in November.

National nominating conventions only come once every four years and no matter how strong they think their electoral advantages are, the nominees cannot simply take a pass on breaking new ground and presenting new ideas in their marquee acceptance speeches. But that's exactly what Clinton did.

Just about every headline and lead paragraph in the media coverage on Friday looked like it was written days ago. They each used the word "historic" in their headlines and focused mostly on the fact that Hillary Clinton is a woman. But those were the same headlines and lead paragraphs the newspapers and news websites used when she clinched the nomination in the primaries and again when she was formally nominated on the convention floor! The coverage of Clinton's speech, even by the mostly sympathetic news media, told you that there was really nothing new to see here.

Clinton's campaign surrogates and her other allies had spent days promising her speech would break new ground. We were told we'd hear about a bold infrastructure plan, more details about her Bernie Sanders-inspired free college tuition policy, and more. These issues were mentioned, but not even the mostly Clinton-sympathetic mainstream media bothered to mention them prominently.

But while there wasn't anything really new, there was something clear: Hillary Clinton and her team are definitely OK with making this election all about Trump. Even after several convention speeches gutting Trump during the previous three nights, Clinton still carved out sharper slams against her opponent, especially when she focused on his "I alone can fix it" claims. Making the election about Trump doesn't seem like the worst campaign strategy for a number of reasons, especially because Trump is such a volatile candidate. But sharpening the assault on Trump was only half of the job for Clinton Thursday night.

She failed to deliver the other half, which was giving the voters something to connect them emotionally with her. She did try to achieve emotional connections by telling some more personal stories about her childhood and even referring to her religion. But I don't think they were effective.

She would've been better off using other people's stories for an emotionally-laden pitch for any one of several policies she's embraced over the course of this presidential run. She could have talked much more about the slain Muslim Iraq war hero whose father gave such an emotionally stirring attack on Trump's immigration policies earlier that night. She could have pulled out a particularly touching story about a Syrian refugee family to emotionally shame Trump and his supporters who are slamming her proposal to allow so many more Syrian immigrants into the country.

She could have courted Sanders voters even more effectively by creating new emotionally charged anger about college costs by using the same kind of vitriol she's used to attack pharmaceutical companies and Wall Street and apply that to the universities who keep jacking up tuition way beyond the rate of inflation. And, with a decent number of young women voters still undecided, she could have referenced an emotionally charged story about a woman who suffered because she couldn't get access to an abortion.

Clinton failed to mention the words "refugee," "Muslim," or even "abortion" even once during the entire speech. Feel free to scoff at the use of melodramatic imagery in an election speech, but it's just this kind of emotional triggering that works with voters and always has. But the Clinton team is playing it way too safe to realize this. When it comes to emotions, they're all in on stoking fears and hatred of Donald Trump and don't have any chips left to bet on anything else.

Clinton quoted President Franklin D. Roosevelt last night when she said "the only thing we have to fear is fear itself." She should take her own advice. Her fear of breaking new ground in this election and in her campaign strategy will be her undoing. When elections become all about one new candidate with a dynamic and exciting personality, (love it or hate it), they are almost always won by that new candidate. Thursday night was Clinton's best chance to make the election at least partly about something other than Trump, and she blew it.

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

For more insight from CNBC contributors, follow @CNBCopinion on Twitter.