The best convention speech? Well, this was the most unusual.

Michael Bloomberg's speech at the Democratic National Convention was unique in that he is an unrepentant independent. That made it potent. 

What was the best speech at either the Democratic or the Republican convention? Let me tell you which one I think was the most important by far for America’s future.

But first, let me underscore my bias, which is right there in my opening paragraph. I am selecting the best speech in terms of which is most important for America’s future.

Obviously Michelle Obama’s speech was magnetic in drawing support to Hillary Clinton. Ivanka Trump also dazzled her audience with her full-throated endorsement of her father. Muslim Gold Star father Khizr Khan’s speech brought tears to my eyes, and African-American pastor Mark Burns inspired Republicans to leap to their feet applauding diversity.

But frankly, in terms of “America’s future,” none of these talks broke through the two-polarized-parties paradigm. In Cleveland, they bowed down before the Republican Party and its new savior. In Philadelphia, they worshipped at the altar of the Democratic Party and its pantheon of heroes — and now, a history-making heroine.

However, in my opinion, one speaker most effectively transcended party politics and addressed America’s future. That person was former New York Mayor Michael Bloomberg.

Announcing from the outset that he intended to give an “unconventional convention speech,” he kept his promise. He also said unequivocally, unlike every other speaker, that he was not a member of either party – and proud of it.  By the time he finished the second sentence of his speech, he had already broken new ground. He had identified himself as a proud “Independent” who, as he later explained, found good ideas (and bad) in both parties, and who intended to decide for himself, in every election, who was the best person for the job.

Admittedly, his oratory was neither eloquent nor transformative. His most-quoted line – “I know a con when I see one” – illustrated his style, which was more taxi driver than statesman. Nevertheless, the thrust of his talk pointed the way toward an America that cares about problem-solving rather than sloganeering.

It is true: He eventually took sides when he plainly stated his firm intention to vote for Mrs. Clinton for president. But he made crystal clear – unlike almost every other speaker – that this had nothing to do with “D” following her name on the ballot.  Precisely because he was an independent, I found his endorsement of the former secretary of State to be more compelling than any other. It was Mr. Bloomberg’s dogged independence that made his commitment to work for her all the more inspiring.

It was Bloomberg, not Clinton or the other Democratic headliners, who breathed life into the party’s “Stronger Together” motto.

The real meaning of “Stronger Together” runs far deeper than asking Democrats to overcome their differences and support Clinton. It actually means that the tribal warfare between the Trumpites and the Clintonites has to end. Neither army is going to magically disappear. Both will still be alive and well on Nov. 8. So a real leader needs to have the courage to say to the devotees of both candidates: “Stop attacking your neighbors and start collaborating.”

The speaker who most effectively conveyed that message was Bloomberg. May he step forward to serve the next administration with distinction. And may the next president be wise enough to ask him.

Mark Gerzon, president of Mediators Foundation, is the author of "The Reunited States of America; How We Can Cross the Partisan Divide." He writes his Beyond Red & Blue blog exclusively for Politics Voices.