If Microsoft, perhaps our most competitive company, has to abandon the U.S. in order to continue to thrive, who exactly is going to stay?

At issue is Obama’s policy to end the deferral of multinational taxation.

The U.S. now has about the highest combined corporate tax rate, second only to Japan among industrialized countries. That rate is so high that U.S. firms have an enormous disadvantage versus competitors. The average corporate tax rate for the major developed countries in the Organization for Economic Cooperation and Development in 2008 was about 27 percent, more than 10 percentage points lower than the U.S. rate.

So the question is, why does Obama advocate a policy that so flies in the face of everything that economists have learned?

I have to admit I am at a loss. Maybe it is good politics to bash American corporations, and Obama isn’t really serious about making this change happen.

But if the change is enacted, and domestic corporate taxes aren’t reduced to offset the big tax hike, the result will be a flight from the U.S. that rivals in scale the greatest avian arctic migrations.

If that occurs, the firms that stay in the U.S. will be at such a huge tax disadvantage that they will absolutely need a “rescue.”

(Kevin Hassett, director of economic-policy studies at the American Enterprise Institute, is a Bloomberg News columnist.