Elizabeth Warren has blown it. In just one speech this week, she may have ended any chance she had to become Hillary Clinton’s running mate.

When the two took the stage at Cincinnati’s Union Terminal on Monday, they looked like a dynamic duo. Warren is 67, and Clinton is 68, and though that used to be on the verge of old age for presidential politics, it has become the new “seasoned.” (Barack Obama was 47 when he was elected. George W. Bush was 54. And Bill Clinton was 46.)

Both Warren and Hillary wore shades of blue — certainly no accident. They are such a pair they even dress alike! Both have short blond hair. Both looked energetic, vigorous and enthusiastic.

Then they started speaking. And it was all over.

Warren was just too darn good. She went after Donald Trump like a hobo on a ham sandwich. She delivered a barnburner, a blockbuster, a foot-stomper of a speech.

If one purpose of a political speech is to define your opponent, she had that down pat.

Trump, she said, is “a small, insecure money-grubber” who “cares about no one but himself.”

Trump “will crush you into the dirt to get whatever he wants.”

“Trump says he’ll make America great again. … It’s stamped on the front of his goofy hat. You wanna see goofy? Look at him in that hat.”

The audience roared and clapped and held its sides. Oh, that hat! That baseball cap that seems as if it is stapled to Trump’s scalp. (He wears it to keep his hair from getting mussed. You do not want to be around Trump when his hair gets mussed.)

And that “Make America Great Again” motto? When did America stop being great? When it started making such guys as Trump presumptive nominees for president?

Who is Donald Trump anyway? How much do you really know about him except that he actually managed to lose money on a casino? Which takes a special kind of skill.

The Clinton campaign strategy regarding Trump is to continue to get under his skin, continue to poke him with a stick because when he gets angry, which is pretty much all the time, he loses control of his mouth.

He talks about thousands of imaginary Muslim Americans dancing in the streets after 9/11. He talks about how Mexican immigrants are rapists. And he says of John McCain: “He’s not a war hero. He’s a war hero because he was captured. I like people that weren’t captured.”

Trump also likes people who got out of the draft because of bone spurs — people like him.

Warren, the senior Democratic senator from Massachusetts, has been designated an official stick-poker.

Warren summed it all up in a video released last week. “I have to be honest,” she said. “It is hard to talk about Donald Trump. Between his ignorance, his racism, his sexism, his lies — it is actually hard to know where to start.”

Boom! Drop the mic.

But that is the problem. If you want to become the vice presidential nominee, you do not want to outshine the presidential nominee.

True, Clinton seemed to be wowed by Warren’s speech Monday, too.

“You just saw why she is considered so terrific, so formidable. Because she tells it like it is,” Clinton said. “I must say, I do just love to see how she gets under Donald Trump’s thin skin.”

And it would be nice for Clinton to be able to sit back and talk about foreign policy and fiscal policy and all the other policies that Trump knows nothing about and let her running mate do the nasty stuff.

The trouble is, however, voters rarely cast ballots because of who is running for vice president. Clinton has to thread the needle and pick a running mate who can shine, but not outshine.

And nastiness runs both ways. “Crooked Hillary is wheeling out one of the least productive senators in the U.S. Senate, goofy Elizabeth Warren,” Trump tweeted Monday.

On Tuesday, Warren said: “What this is really about is, can they bully me into shutting up? Can they just be nasty enough and ugly enough and throw enough stuff in my direction that I’ll say ‘oh’ and just go back into the shadows? And the answer is, nope, not happening.”

The same is true for Clinton. Last Wednesday, Trump called her perhaps “the most corrupt person ever to seek the presidency.”

“Clinton has perfected the politics of personal profit and even theft,” Trump said. “She ran the State Department like her own personal hedge fund, doing favors for oppressive regimes and many others … in exchange for cash, pure and simple.”

And that wasn’t all. “Her decisions spread death, destruction and terrorism everywhere she touched,” Trump said.

But isn’t this all just name-calling — just another part of the national entertainment, the national pastime that we call a presidential campaign?

Hillary Clinton doesn’t care. This time next year, they can call her whatever they want — just as long as it’s “Madam President.”

Roger Simon is Politico’s chief political columnist. His new e-book, “Reckoning: Campaign 2012 and the Fight for the Soul of America,” can be found on Amazon.com, BN.com and iTunes. To find out more about Roger Simon and read features by other Creators writers and cartoonists, visit the Creators webpage at www.creators.com.

Photo: Hillary Clinton stands along side Senator Elizabeth Warren at a campaign rally in Cincinnati, Ohio. REUTERS/Aaron JosefczykHillary Clinton stands along side Senator Elizabeth Warren at a campaign rally in Cincinnati, Ohio. REUTERS/Aaron Josefczyk