Editor's Note: (Eric Liu is founder of Citizen University and executive director of the Aspen Institute Citizenship & American Identity Program. His books include "A Chinaman's Chance" and "The Gardens of Democracy." He was a White House speechwriter and policy adviser for President Bill Clinton. Follow him on Twitter: @ericpliu. The opinions expressed in this commentary are his.)
(CNN) On Wednesday night in Cleveland, it looked like we might return to the conventions of a normal convention.
There were robust statements of Republican ideology, crowd-pleasing defenses of the Second Amendment and denunciations of radical Islam. No plagiarism or loopy references to Lucifer. Marco Rubio and Scott Walker both praised the man who'd vanquished them in the primaries.
But ultimately, there was only one winner Wednesday. And it wasn't Donald Trump or his running mate, Mike Pence, who was supposed to be the focal point of Wednesday's program.
It was Ted Cruz.
Cruz did more than outshine Trump; he force-fed him an ice-cold dish of revenge. He did more than make the negative case against Hillary Clinton; he made an affirmative case for freedom that no one else had been able to make this week. He did more than shout and scream; with rhetorical deftness, he got the crowd more engaged and excited than any other speaker.
That is, until he decided to tell Americans to "vote your conscience." With this pivotal and pointed non-endorsement of Donald Trump, he lost the crowd, who began to boo and heckle him vigorously. Cruz powered through the rest of his remarks, speaking straight to the camera and ignoring the chaos on the floor as Trump hovered angrily in the wings.
It was the most remarkable moment of live political theater in recent memory. And it ensured that for the third day in a row, Trump's campaign would lose total control of the narrative of its own convention.
Yes, every aspect of Cruz's performance was calculated and self-serving. Certainly, he burned bridges with plenty of conventioneers. But what Cruz did was supremely gutsy. It was savvy. And it must have been deeply satisfying payback for all Trump's insults and attacks during the primaries.
If Trump loses, Cruz put himself in position to be the biggest GOP figure to refuse to get on board with Trump -- and the only one to defy Trump on his own stage. A notorious lone wolf loathed by his Senate colleagues, Cruz will now get to recast his overweening self-absorption and ambition as conscience and high principle.
But most of all, he clarified the moral choice that all Republicans will face as their party implodes. By getting hitched with an ideologically impure candidate like Trump, will rank-and-file Republicans undermine the conservative cause of liberty?
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Even if Trump wins, Cruz gets to be the voice of pure-bred, limited-government conservatism who will lead a grassroots army every time the Trump administration tries to pivot to the center. Either way, Cruz doesn't lose.
To be very clear, I find Cruz's ideas and policy proposals wrongheaded and often odious. But he did the country a service Wednesday by dramatically exposing the fact that a vote for Trump is not a vote of conservative principle. It is a vote for an unqualified authoritarian bigot.
Cruz sent a message to the voters Wednesday that Trump himself should've remembered when he put Cruz on the program: Buyer beware.