The usual suspects on the left are very concerned that Obama is pushing too many temporary tax cuts and not enough government spending in his constantly evolving stimulus package. But how much money can the federal government really pour into public spending? Harvard professor Ed Glaeser notes:

While the mechanics of a payroll tax cut are simple, spending hundreds of billions wisely on infrastructure is hard. Currently, the federal government spends about $40 billion a year in transportation, and another $20 billion on other forms of infrastructure. There is a case for significantly increasing this amount. Our roads do need repairing, and it makes sense to invest more in a downturn when unemployment is high. But even doubling the current federal infrastructure expenditure, a vast increase, would represent only 8 percent of a $750 billion package.

The country needs to invest steadily and wisely on infrastructure, not rush hundreds of billions of dollars out the door. Really expensive projects, like the Big Dig, can take many years to plan, permit, and build. Our roads require ongoing maintenance, not a big push. Moreover, fairness and economic efficiency dictate that infrastructure should generally be paid for by users, not general tax revenue. It is appropriate that gas taxes pay for federal highway aid. Using general revenues to build highways means more subsidies for carbon-emitting cars. The country should take infrastructure investment seriously, but infrastructure spending is unlikely to be sound stimulus.

Also at Harvard, Greg Mankiw posts a reader’s thoughts on the stimulus:

I work for the DoD and when the Department of Homeland Security was established,we helped them with many things, not the least of which was contracting. To make a long story short, you cannot juice up a government agency’s budget by tens of billions (or in the case of the stimulus package, hundreds of billions) and expect them to be able to process the paperwork to contract it out, much less oversee the projects or even choose them with any kind of hope for success. It’s like trying to feed a Pomeranian a 25 lb turkey. It’s madness.

It was years before DHS got the situation under control and between the start and when they finally assembled a sufficiently capable team of lawyers, contracting officials, technical experts and resource managers, most of the money was totally wasted. Now take the DHS situation and multiply it by 20 and you’ve got the Obama stimulus package. Even if they hand the money to existing governmental agencies, the situation will be the same. Those existing agencies are working full time administering the budgets they have. They can’t just add a zero at the end of each contract and be done with it.

The left wants the government to spend money for the sole sake of spending money. Our economy can’t afford all that public spending to crowd out private investment today and our children can’t afford all that debt in the future.