One would think that with one of the weakest economic recoveries on record, President Obama would be desperately searching for ways to promote economic growth. It is, after all, an election year. Most pundits and pollsters agree that it’s the economy, stupid.

Instead, Mr. Obama used his State of the Union speech to rail on about fairness, inequality, and redistribution. The Obama strategy is simple: Tax the rich because they don’t pay enough.

The problem is, they do pay enough. According to the Tax Foundation, Americans making $1 million or more pay a 25% average tax rate. People in the $50,000 to $100,000 income category — call it the middle class — pay 7% to 8%.

But no, Mr. Obama’s one big idea in his Tuesday-night speech was a 30% minimum tax on millionaires. This, by the way, is really a hike in the capital-gains tax. And this Obama penalty is aimed squarely at his likely election opponent, Mitt Romney. Talk about taxing success. Talk about taxing growth.

The capital-gains tax is the single most important economy-wide tax on wealth, risk-taking, and investment. It’s a tax on seed corn. What a brilliant idea, Mr. President.

I remember the late Jack Kemp always saying you can’t have successful capitalism without capital. But that wasn’t in the president’s State of the Union.

It’s not as though the economy is prepared to a take another tax hit. The fourth-quarter GDP report adjusted for inflation came in at a mediocre 2.8%. Wall Street promptly sold off on the news.

We’re now 10 quarters into the tepid Obama recovery, with its average quarterly growth rate of 2.4% annually.

Deep recessions are supposed to breed strong snap-back recoveries. But it’s not happening — even after an $800 billion government-spending package, a $2 trillion Federal Reserve balance-sheet expansion, a zero Fed interest rate (for three years and counting), and a whole bunch of temporary targeted tax cuts.

It’s the whole Keynesian bag of tricks, but it’s still a subpar recovery.

Way back when, Ronald Reagan used the supply-side model, and rejected big-government Keynesianism. He permanently lowered marginal tax rates, deregulated the economy, went to a strong King Dollar that collapsed oil and gold prices, and limited domestic spending (as a share of GDP). After ten quarters of recovery, the Reagan growth rate was 6%.

Compare that to Mr. Obama’s 2.4%. Or compare Mr. Obama’s 2.4% to the 4.6% post-WWII average recovery rate after ten quarters. The average is twice as good as that under Mr. Obama. But Mr. Obama is only roughly a third of Reagan. That tells you something.

On top of all this, under current-law Obama policy, the vitally important capital-gains tax is going up, even without the millionaire’s minimum. Next year, the capital-gains tax will revert to 20% from today’s 15%. Then Obamacare will raise investment tax rates by 4%, bringing us up to 24%. That equals an 11% rollback of wealth and growth incentives.

That’s not all, since the capital-gains tax is paid on top of the 35% corporate tax. So under Mr. Obama, a 24% cap-gains tax is really a 51% tax rate on capital.

As Mitt Romney found out, even today’s 15% cap-gains tax is really a 45% double tax on top of the corporate levy. But there’s a better way here: Slash the corporate tax rate, and leave the cap-gains rate alone until full-fledged tax reform can take place.

In other words, increase incentives to grow and invest. Make it pay more after tax to invest and take risks. That’s a growth prescription, the exact opposite of Mr. Obama’s redistributionism.

Why is it fair or equal to create a lower tide that pulls down all boats?

I interviewed Mitt Romney on CNBC this week, and it’s clear that he gets this. As he aggressively argued in the Jacksonville, Fla., debate, he is proud of his success and doesn’t want to give it back to the tax man.

More important, Team Romney is cooking up a stronger tax-reform plan. Mr. Romney intends to broaden the base by getting rid of deductions, exemptions, and loopholes, and then bring down the rates. I asked him if the plan would be ready during the primary season. He said yes.

There is a growing consensus around the country for full-fledged reform of the personal and corporate tax codes. People yearn for simplicity, competitiveness, and new incentives. Mr. Obama’s great mistake in the State of the Union was his low-ball vision of class warfare and redistribution when the country wants growth measures.

This November we’ll see a great debate between a big-government entitlement society that emphasizes fairness and a smaller-government growth society based on free-market capitalism. Pro-growth tax reform is essential to this debate.