Kamala Harris is running a campaign against herself.

The vice president is a left-wing Democrat with an unsalable record in office.

So candidate Harris pretends to be something else — a newcomer with a happy message and a bevy of Republican supporters.

The trick isn’t working, as recent polls favoring Donald Trump demonstrate.

It’s almost as if nobody — independents, Republicans or Democrats — associates Dick Cheney with good vibes.

Yet Harris is out on the trail boasting of his support.

Harris was counting on winning the election by surprise, replacing Joe Biden on the Democratic ticket before voters could stop to ask what they were getting.

She put off doing major interviews as long as she could, for fear they’d lead to exactly the difficulties everyone saw in her appearance last week.

The vice president didn’t want to be asked about her record:

Month-on-month inflation peaked above 9% midway through the Biden-Harris years.

She’s a border czar presiding over a broken border, while in foreign policy Harris and Biden have delivered only humiliation and horror from Afghanistan to Ukraine and the Middle East.

Four more years of the same isn’t a pitch voters will go for.

Instead, Harris tries happy talk — but she’s not at all pleased when voters talk back.

“You guys are at the wrong rally,” she scolded attendees who shouted, “Jesus is Lord!” at a Wisconsin stop.

Her campaign messaging is growing increasingly apocalyptic — and hypocritical.

Democrats have waged nonstop “lawfare” against the Republican nominee.

Yet Harris insists it’s Trump who wants to use government power against his opponents.

Trump isn’t a soft-spoken campaigner, to say the least.

But his genius lies in combining galvanizing rhetoric with disarming humor.

He was in his element last weekend when he stopped by a Philadelphia-area McDonald’s to try his hand as a fry cook.

Trump had a political point to make — he was teasing Harris about her claims to have worked for the fast-food giant when she was in college.

But that jab was secondary to the sheer merriment of having Trump don a cook’s apron and learn to scoop fries, as the restaurant’s regular employees looked on and smiled.

The scene spotlighted the kind of joy that’s in short supply inside Harris’ campaign.

The contrasting emotional resonances couldn’t be sharper — Trump and the golden arches of America’s most popular burger chain on one side, Harris and everything voters associate with Dick Cheney on the other.

Yet Harris has good reason to tout ties to yesterday’s Republicans-because she hardly wants to be identified with today’s Democrats, least of all with her record alongside Biden.

Her only hope is to run as an outsider to her own administration.

The Republicans she’s using to weave the illusion that she’s something other than a typical Democrat, however, are the farthest thing from outsiders:

Indeed, that’s why they’re endorsing her — they’re insiders angry about Trump’s war on the political establishment.

The Cheneys feel closer to Harris than they do to the grassroots Republicans who booted Dick’s daughter Liz out of Congress.

The Harris campaign is a last redoubt for the old guard in both parties, Cheney Republicans and Biden-Harris Democrats alike.

Harris likes to talk about “what is possible, unburdened by what has been.”

But Harris is nothing if not burdened by what she has been, and now she’s looking to Republicans out of the past to save her from voters’ judgment about the present administration.

She wanted to run on vibes, but now they’ve all turned bad — and Trump, after surviving two assassination attempts, has become the more joyful campaigner.