Rep. Joe Kennedy III (D-Mass.) gives message to 'dreamers' in Spanish during the Democratic response to President Trump's State of the Union address on Jan. 30, 2018. (Reuters)

Whenever a party seems to be approaching a major victory, pundits and journalists will be gripped by the impulse to warn that they’re Doing It Wrong, and they either won’t win at all or, if they do, their victory will be hollow unless they take the scolder’s advice.

So it has been lately with Democrats, who are being constantly told that, while it looks like they’re headed for a wave election this November, if they don’t come up with a positive, affirmative message that has nothing to do with anger at President Trump, then they don’t deserve to win.

That notion is wrong on both counts: they don’t need a “positive” message as it is often defined, and anger at the president is not just sufficient, it’s the most morally and politically appropriate message for 2018.

As a way to think about this, I’d like to look at the Democratic response to the State of the Union, which was delivered last night by Rep. Joe Kennedy (D-Mass.). Put aside the stupid questions about him — Should the Democrats be promoting the scion of a royal family? Was he wearing too much lip balm? — and focus on the content. Kennedy’s speech mentioned policy issues, but mostly it was an attack on Trump and the Republicans, delivered through a contrast of values. Here’s a key passage:

This administration isn’t just targeting the laws that protect us — they are targeting the very idea that we are all worthy of protection. For them, dignity isn’t something you’re born with but something you measure. By your net worth, your celebrity, your headlines, your crowd size. Not to mention, the gender of your spouse. The country of your birth. The color of your skin. The God of your prayers. Their record is a rebuke of our highest American ideal: the belief that we are all worthy, we are all equal and we all count. In the eyes of our law and our leaders, our God and our government. That is the American promise.

You might say: “That won’t persuade the fellas in MAGA hats the New York Times keeps interviewing down at that diner in West Virginia!” And you’d be right. It is an appeal to liberal values of equality, inclusiveness, and common fate and purpose. It won’t convince conservatives to vote for Democrats.

But that’s not what Democrats need right now. What they need, more than anything else, is for their base to get energized, excited, and yes, angry. They need to feel that both their values and their interests are under attack by a reckless, impulsive, cruel, infantile president and his enablers in Congress, and that there is no more urgent task than stopping them. Because that is the truth.

Centrist pundits will insist Democrats have to stand for something apart from Trump. But they already do. Ask a Democrat running for Congress what she would like to do about health care, the minimum wage, environmental protections, taxes, or anything else, and she’ll have answers, roughly the same answers as most other Democrats would give. She might not have a bumper-sticker-ready phrase to wrap it all up with, but if you think that’s her problem, then your argument isn’t that Democrats don’t stand for anything. Your argument is that their marketing ought to be better.

And what’s the problem with “I’m against Trump” as a message? It seems to be darned persuasive right now. When people say that Democrats (or anyone else) need an “affirmative” message, what they seem to mean is that the party needs to come up with a bunch of innovative new policy ideas no one has ever thought of before. But why?

Protecting women’s reproductive rights isn’t a newfangled idea, but it’s central to what it means to be a liberal. Safeguarding the right to vote isn’t 21st-century policy whizbangery, but it’s vital to the survival of democracy. And the idea of welcoming immigrants is as old (and controversial) as the country itself.

As for being against Trump, what could possibly be more important right now? If Democrats do manage to take back the House or the Senate, their primary task in the subsequent two years — their only task, really — is going to be thwarting, constraining, and investigating this president and his administration.

There is absolutely nothing the Democrats could do that would be dumber than setting aside their criticisms of Trump to focus solely on some “affirmative” agenda. First of all, when they get spooked by all the “You need a message!” clamor, they usually come up with pablum like their “Better Deal,” which was focus-grouped and poll-tested within an inch of its life and was utterly uninspiring. More importantly, their base is more excited and active than it has been in anyone’s memory, and it’s because of Trump. That’s why Democrats won election after election in 2017, and why even when they fell short they dramatically outperformed their usual showings. That’s why so many Democrats are becoming activists and running for office.

The truth is that in midterm elections, opposing the president works. Indeed, it’s the only thing that does. Anger at President Barack Obama is what got their voters out in 2010 and 2014, enabling the Republicans to take back Congress. Did they have an “affirmative” agenda undecided voters flocked to? Of course not. Almost no one pretends anymore that the Tea Party was motivated primarily by an abstract belief in small government and not sheer venomous hatred of Obama. Likewise, Democratic anger at President George W. Bush is what enabled them to take control of Congress during the 2006 elections.

“But what about the Contract With America?” you say. Wasn’t that an affirmative agenda that helped Republicans win a sweeping victory in 1994? No, it wasn’t. The fact that you remember it is a result of some very clever myth-making on Republicans’ part, a post-hoc explanation that they used to claim they had a mandate for their agenda. The truth is that polls showed that voters had barely heard of the contract. Republicans won in 1994 because their base was riled up by President Bill Clinton’s policies — his tax increase, his effort to reform health insurance, a ban on assault weapons — and their anger over all that was what drove them to the polls.

Right now, Democrats have an agenda which, if you’re so inclined, you can find in their copious white papers and ten-point-plans. And they have a message: Stop Trump.