Larry Kudlow

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 Obama’s plan.

And for that matter, who really expected an unbelievably large $450 billion plan? That’s way more than 50 percent 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 folks want to know. Obama didn’t tell us.

In very 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. But didn’t we learn from Obama Stimulus One that more government spending doesn’t grow the economy or reduce unemployment?

And 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 a very expensive exercise, one that will yield very little or nothing in the way of permanent job creation or economic growth.

Larry Kudlow

Lawrence Kudlow is host of CNBC’s “The Kudlow Report,” which airs nightly from 7 p.m. to 8 p.m.