There is much excitement about a federal “stimulus” plan focusing on state and local infrastructure spending. At first blush, it seems like a pro-growth idea to get unemployed construction workers off the couch and onto the job site building new government highways, bridges, and the like.

However, national income data from the Bureau of Economic Analysis puts some perspective on such government investment ideas. (See Tables 1.1.5 and 3.17)

The government isn’t the only entity that builds “infrastructure.” New semiconductor plants, refineries, and electricity transmission wires are private infrastructure, which is every bit as important to economic growth as government highways. Indeed, U.S. private infrastructure investment is 4.6 times larger than all federal, state, and local investment combined.

The figure shows that gross private domestic investment was $2.1 trillion in 2007. That compared to $340 billion of gross investment for state and local governments and just $123 billion for the federal government. And note that most ($82 billion) of the federal investment was for military hardware, and thus did nothing for our standard of living in the sense of creating consumable products.

What is the policy upshot? It is far more important for the government to create an environment where private investment can thrive than it is for the government to invest itself.

The private sector puts new factories and equipment in place when it can earn at least a normal return on the income generated over future years. The government skims off roughly a third of the return in income taxes (and most of that money dissappears down the economic black hole of transfer spending). A reduction in that skim would cause relatively little government revenue loss compared to the huge leverage effect it would have over the gigantic private sector investment budget.

So, let’s cut the corporate income tax, and while we’re at it, privatize as much state and local infrastructure spending as we can.