President Trump. (Carolyn Kaster/AP)

Philippe Reines has been a spokesman and adviser to Hillary Clinton since 2002, including during the 2016 campaign.

Campaigned in the wrong states. Ineffective message. Uninspiring orator. Represented all that is wrong with Washington. Strengths turned into fatal liabilities. Anti-gun. Made rhetorical gaffes. Investigated. Unique baggage and vulnerabilities. Never ran a business or created a single job. Liar. Lost to an eminently beatable opponent.

That’s how the 2016 Democratic presidential nominee was branded.

As were the 2000 and 2004 nominees.

As the 2020 nominee will be.

Yes, President Trump is the least-qualified person to ever hold the office and is cementing his ranking as the worst president in American history. Winning will be easy, right? Just have a positive message, don’t stoop to his level, be smart about email, thank your lucky stars you aren’t seeking the cursed third term and ride his unpopularity right into the Oval Office.

Oh, this may come in handy: EBay is a great place to get rid of prematurely purchased drapes.

Trump is a freak of political nature. He’s a political Weeble Wobble that never falls down. He makes Ronald Reagan’s Teflon look like Saran Wrap. He says whatever he wants, whenever he wants, wherever he wants. He could stand in the middle of Fifth Avenue and shoot a porn flick. And as hard as it was for Hillary Clinton to run against him, our 2020 nominee will face something we didn’t: the power of incumbency.

Trump will swoop into places such as Moon Township, Pa., aboard the most symbolic political prop of all time: Air Force One. He’ll hold the crowd in the palm of his hand. Carried live by every network — not just Fox News. Because he is right when he says he is good for ratings. And be careful not to take too much heart in Democrat Conor Lamb’s surprisingly strong performance in Tuesday’s special election in Pennsylvania. Lamb wasn’t running against Trump. You will be.

In 2012, Barack Obama didn’t wait for the traditional post-convention starting gun before defining Mitt Romney. As we saw at this weekend’s rally for someone he barely mentioned, Trump has already started. By the time you’re traipsing across Iowa, he’ll shellac you as a group and vilify you individually: You’ll kill the economy with a new Obamacare; repeal the Second Amendment; the world doesn’t know it yet, but some of you are pedophiles. You’re the biggest liar of all time. Just ask the biggest liar of all time.

If you think you are immune to the above, keep your day job.

But if you’re game to enter an even more vitriolic and bizarre world than 2016, a few suggestions:

●Go high when you can. But when he goes low, take advantage of the kneeling to knock his block off.

●Don’t apologize. Ever. Not over money you took from Harvey Weinstein. Not even for attacking the pope. In fact, proactively attack the pope. Your kid is a shoplifter? You’re proud of them for exposing inadequate security.

●A lot of industries are going to want to hedge their bets. Don’t declare you won’t take money from lobbyists. Take cigarette money. Counterfeit your own.

●Swing at every pitch. Trump never says, “I’m not dignifying that with an answer.” He has no dignity. He leaves no attack unanswered. I spent 15 years recommending ignoring stupidity. “It has no legs. Don’t give it oxygen. There’s no pickup.” I was wrong.

●Do it yourself. Every time. On camera. Online. Surrogates are no match.

●Don’t cede Fox News.

●Boast. Gloat. About your accomplishments. Your biceps. Your everything. You didn’t co-sponsor; you got it done on your inevitable path to Mount Rushmore.

●Don’t wait for post-debate polls. You won. It’s obvious. Everyone saw. Say it onstage.

●Work the refs. The media are going to mess with you. Don’t rely on them. Call them out. You’re running for president of the United States, not the National Press Club.

●Don’t think you can spend as little as he did. The impact of political ads is waning — but don’t be the first to experiment with ceding the airwaves. The Republican National Committee and his PACs won’t.

●Say what you need to say in the primaries. Then say what you need to say in the general. You’ll make it right.

●Bulldoze third-party candidates. Even if you can peel only 10 percent off, peel them off.

●Resign your office. No distractions or ethical lapses. Run against your office.

●Don’t hire anyone who says they’d rather lose than stoop to his level. If you say it, get out of the way for someone living in the real world.

●Deride Clinton at your peril. Nearly 17 million people voted for her in the primaries — 4 million more than the runner-up. And almost 66 million voted for her on Election Day — nearly 3 million more than Trump. Focus on what she is, not isn’t: smart; savvy; tough; still beloved by tens of millions who don’t want to hear you trash her. Her endorsement is invaluable. If you think her loss was a missed layup, you’ll learn the hard way it was a three-pointer.

Lastly, if you don’t find any of this sobering, this should:

This time, he knows he can win.