Like most Americans, we deplore Congressional gridlock. But a hundred billion dollar legislative train speeding down the tracks scares us too.

By all reports, there is rare agreement between the White House and Capitol Hill on the need for a fiscal stimulus package for the flagging economy. There appears to be agreement on the size and scope of the package, so as the details are finalized, we offer some advice.

The first rule should be a sort of economic Hippocratic Oath – first do no harm. Long-term changes to the tax code, tacking on unrelated pet projects, or significantly increasing the national debt for the sake of quickly passing a short term stimulus package are all examples of how Congress could take a temporary problem – a recession – and do lasting damage to the economy. Any stimulus should be targeted, limited, simple, and temporary. These guidelines will help avoid digging deeper into the economic hole (pdf) that we are in.

There is scant evidence supporting one type of stimulus over others. A 2002 Congressional Budget Office (CBO) report compares the tradeoffs inherent in many of the more popular proposals for priming the economy. In the end it comes down to predicting individual behavior – a favorite pastime of economists. That said, a more recent CBO report proposes three fixes that at least do minimal harm: temporary tax cuts and rebates, temporarily extending or expanding unemployment benefits, and temporarily increasing foods stamps. Other economists suggest tax breaks and incentives for business investment, such as temporary provisions for accelerated depreciation on new equipment purchases.

A stimulus package aims to inject money into a stagnant economy with the consequent outcome being greater consumer spending. The trick is getting the most short term consumption for the least long term cost – either with tax cuts, spending increases, or some combination thereof.

One challenge is that it is difficult to pinpoint exactly when the economy has begun to tank. In fact, the recession may have already started and may be over by the time the stimulus is enacted – actually creating an inflationary rather than stimulating effect. Regardless, we won’t even know for certain the depth of the current problem until the final arbiter on recessions, the National Bureau of Economic Research, weighs in, which will not happen until later this summer.

Congress should quickly get a “Hippocratic” stimulus package done and then get down to the business of working on a long term plan to get our spending house in order, starting with figuring out what to do about the looming and ballooning entitlement costs that are coming with the retirement of all those baby-boomers. It also wouldn’t hurt to develop future generic stimulus packages that could be automatically triggered when the next economic slump begins. This might help with the historic problem of Congress passing a bucket of stimulus after the economic fire is already out. In the end, clear headed thinking and long term solutions are the real boosts to the economy.