According to an article in the New York Times, the Obama Administration is seriously examining a proposal to reduce America’s anti-competitive 35 percent corporate tax rate.

The Obama administration is preparing to inject an unpredictable new variable into its economic policy clash with Republicans: a plan to overhaul corporate taxes. Economic advisers have nearly completed the process initiated in January by the Treasury secretary, Timothy F. Geithner, at President Obama’s behest. That process, intended to make the United States more competitive internationally, has explored the willingness of business leaders to sacrifice loopholes in return for lowering the top corporate tax rate, currently 35 percent. The approach officials are now discussing would drop the top rate as low as 26 percent, largely by curbing or eliminating tax breaks for depreciation and for domestic manufacturing.

This may be a worthwhile proposal, but this is an example where it would be wise to “look before you leap.” Or, for fans of Let’s Make a Deal, let’s see what’s behind Door Number 2.

To judge Obama’s plan, it is important to have the right benchmark. An ideal corporate tax system obviously should have a low tax rate. And it also should have no double taxation (tax corporate income at the business level or tax it at the individual level, but don’t tax it at both levels).

But it’s also important to have a simple and neutral system. The right definition of corporate income for any given year is (or should be) total revenue minus total costs. What’s left is income.

This may seem to be a statement of the obvious, but it’s not the way the corporate tax code works. The system has thousands of complicated provisions, some of which provide special loopholes (such as the corrupt ethanol credit) that allow firms to understate their income, and some of which impose discriminatory penalties by forcing companies to overstate their income.

Consider the case of depreciation. The vast majority of people understandably have no idea what this term means, but it sounds like a special tax break. After all, who wants big corporations to lower their tax bills by taking advantage of something that sounds so indecipherable.

In reality, though, depreciation simply refers to the tax treatment of investment costs. Let’s say a company buys a new machine (which would increase productivity and thus boost wages) for $10 million. Under a sensible and simple tax system, that company would include that $10 million when adding up all their costs, which then would be subtracted from total revenue to determine income.

But the corporate tax code doesn’t let companies properly recognize the cost of new investments. Instead, they are only allowed to deduct (depreciate) a fraction of the cost the first year, followed by more the next year, and so on and so on depending on the specific depreciation rules for different types of investments.

To keep the example simple, let’s say there is “10-year straight line depreciation” for the new machine. That means a company can only deduct $1 million each year and they have to wait an entire decade before getting to fully deduct the cost of the new machine.

Ultimately, the firm does deduct the full $10 million, but the delay (in some cases, about 40 years) means that a company, for all intents and purposes, is being taxed on a portion of its investment expenditures. This is because they lose the use of their money, and also because even low levels of inflation mean that deductions are worth significantly less in future years than they are today.

To put it in terms that are easy to understand, imagine if the government suddenly told you that you had to wait 10 years to deduct your personal exemption!

Let’s now circle back to President Obama’s proposal. With the information we now have, there is no way of determining whether this proposal is a net plus or a net minus. A lower rate is great, of course, but perhaps not if the government doesn’t let you accurately measure your expenses and therefore forces you to overstate your income.

I’ll hope for the best and prepare for the worst.

P.S. It’s also important to understand that a “deduction” in the business tax code does not imply loophole. If you remember the correct definition of business income (total revenue minus total costs), this means a business gets to “deduct” its expenses (such as wages paid to workers) from total revenue to determine taxable income. Some deductions are loopholes, of course, which is why a  simple, fair, and honest system should be based on cash flow. Which is how business are treated under the flat tax.