Who would have really expected a 300-point stock market plunge on the day after President Obama’s so-called jobs speech?

Yes, worries over new fears of a Greek default ripped through the markets on Friday. As did fears of an al-Qaeda bombing plot on the tenth anniversary of 9/11. But you can’t help but think that at least some of the stock plunge is a signal of no economic confidence in Mr. Obama’s plan.

For that matter, who really expected an unbelievably large $450 billion plan? That’s way more than 50% of the original $800 stimulus package in 2009 — which did not work.

Leaked reports leading up to the speech suggested a $300 billion plan — already way too big. But $450 billion? At a time of massive deficits and debt? And a downgrade? How is this going to be paid for? That’s what many want to know. Mr. Obama didn’t tell us.

In round numbers, the package comes to $250 billion of temporary payroll tax cuts of one kind or another, with another $200 billion in new spending on infrastructure, unemployment benefits, and direct aid to state and local governments. Didn’t we learn from Obama Stimulus One that more government spending doesn’t grow the economy or reduce unemployment?

While more than half of the president’s new package is called “tax cuts,” the reality is that these are temporary tax cuts. Even though tax rates are reduced for both employers and employees, it’s just for one year.

That blunts the true incentive impact of the tax cuts. Businesses like to look ahead at least three to five years for their employment planning. And they’re already worried about the tax and regulatory mandate costs of Obamacare, which has become a great deterrent to job creation. But nobody makes clear business decisions based on temporary one-year tax cuts. That’s not the way business works.

The only true incentive effects come from permanent, economy-wide reductions in tax rates. And that’s what’s been missing all along from Team Obama’s thinking.

For example, it is quite possible that some new jobs will be created in election-year 2012 as a result of the temporary payroll tax cuts. But those jobs will be borrowed from 2013, when the economy risks expiring as the temporary tax cuts go away.

So this becomes an expensive exercise, one that will yield little or nothing in the way of permanent job creation or economic growth.

The president does talk about corporate tax reform, but he has no specifics on it. He never mentions the tax-free repatriation of $1 trillion in overseas profits booked by U.S. firms, or for that matter a territorial business-tax approach that would stop the double tax on foreign earnings. This repatriation idea would have been a layup. The whole world wants it. But not the White House.

Out on the campaign trail, Governors Romney, Huntsman, and Perry and other GOP candidates are talking about fundamental tax reform for individuals and businesses, the kind that can provide the permanent incentive effects needed to supercharge the economy. But not the White House.

Out in the business community, everyone is talking about a regulatory moratorium, or rollback, to lower the cost structure of doing business. But Obama only talks about this in the vaguest terms.

Stop the NLRB and EPA. Hold back on Dodd-Frank and Sarbanes-Oxley. Provide confidence on taxes and regulations for the whole private-investment sector.

Nope. Not the White House. President Obama’s latest vision on taxes once again singles out energy companies, successful high-end earners, and small-business entrepreneurs for future tax hikes, rather than across-the-board rate-flattening and deduction-ending.

The best part of Mr. Obama’s speech was the segment about free-trade agreements with Panama, Colombia, and South Korea. But somehow this never gets done.

As for infrastructure spending, it has its place (though not a Fannie Mae-like bank). But America needs new incentives to propel entrepreneurship and dynamism for brand-new business start-ups and technologies. And throwing more money at state-and-local-government unions is just a pathetic political bailout.

What we really need is a long-term program that gets government out of the way and lowers spending, tax, and regulatory barriers wherever they exist. But at bottom, the president’s plan is a big-government plan. It’s not a private-sector plan.

If left to its own devices, America’s free-market capitalism will produce growth and jobs. But it won’t happen in a targeted and temporary straight jacket.