It isn’t just a Beatles song, it’s America’s reality: It’s getting better all the time. So why are Democrats so wedded to the ­notion that America sucks and ­always has?

Sure, they have to poke holes in President Trump’s accomplishments and pretend things aren’t as rosy as they seem. But they take things far beyond that.

Nancy Pelosi sat behind Trump during his State of the Union ­Address looking like she was sorting through her mail. She would look up every once in a while to shake her head, as if the numbers he was touting were untrue.

“Nearly 5 million Americans have been lifted off food stamps.” “Unemployment has reached the lowest rate in over half a century.” “More people are working now than at any time in the history of our country — 157 million people at work.” These aren’t Trumpian boasts — they are empirically verifiable facts.

In her response for the opposition, Michigan Gov. Gretchen Whitmer questioned the economic data. “American workers are hurting,” she said. “In my own state. Our neighbors in Wisconsin. And Ohio. And Pennsylvania. All over the country. Wages have stagnated, while CEO pay has skyrocketed.”

But the numbers don’t lie. Gallup’s Mood of the Nation poll last week “recorded a 20-year high in Americans’ confidence in the US economy.”

And no, it isn’t just rich people excited about the boom. Writing in The New York Times last month, Ernie Tedeschi, a former US Treasury economist, noted: “These days, wages in the United States are doing something extraordinary: They’re growing faster at the bottom than at the top. In fact, ­recent growth for workers with low wages has outpaced that for high-wage workers by the widest margin in at least 20 years.”

Tedeschi credits state-level minimum-wage increases with this, though that can’t possibly be the full explanation. For starters, as he himself admits, “Wage data will by definition capture only those who stayed employed after an increase. If people were laid off because of a minimum-wage increase, their loss of wages wouldn’t factor into the average.” Plus, minimum-wage work only ­accounts for “around 13 percent of hours worked by Americans in the bottom third of wages.”

Last week, noted denier of facts Rep. Alexandria Ocasio-Cortez ranted about American success and how it is impossible to achieve for those who aren’t born wealthy. Apparently unfamiliar with metaphors and figures of speech, AOC said, “It is a physical impossibility to lift yourself up by a bootstrap, by your shoelaces, it’s physically impossible. The whole thing is a joke.”

The former bartender who, ahem, pulled herself up by her bootstraps and became a congresswoman doesn’t exactly have standing to claim the American Dream is dead. Then again, in America, you can be a millionaire socialist like Bernie Sanders and win the support of a representative who claims success is impossible — ­despite her own.

What a country.

On Twitter, entrepreneur Carol Roth asked people to submit stories of bootstrapping in America with the hashtag #IBootstrapped. Stories poured in. People told Roth of growing up poor and now owning a business, being the first person in their families to go to college, working hard and achieving success.

Some of the most powerful accounts came from people who truly struggled, were homeless, never finished high school, had teen pregnancies — but made it anyway. The American Dream is alive in each one of those stories.

Telling Americans they will never win if they weren’t born rich isn’t just factually wrong, it discourages people from even trying to make it.

Economies are cyclical, and we won’t always be in this upswing. We will have our lows. Let’s save our despair for when things are ­actually going badly.

Right now, things are great, and Americans feel it. The same Gallup poll found that “nine in 10 Americans are satisfied with the way things are going in their personal life, a new high in Gallup’s four-decade trend.” Can Democrats please let us enjoy it?

Twitter: @Karol