A Wall Street Journal editorial today details how liberals in Congress have cooked the books to keep spending increases exempt from paygo rules, but still applies them to tax cuts:

As it happens, the farm bill also exposes the real purpose of paygo — to make spending easier but tax-cutting harder. The farm bill is scheduled to expire later this month and the cost of extending it over 10 years is $597 billion. But does paygo require offsetting all the cost of the farm bill? Heavens no. The cost of extending such entitlement programs is already imbedded into the budget “baseline,” and thus these programs get automatic extensions. Only new and expanded benefits have to be “paid for.”

Meanwhile the Bush tax cuts, which are scheduled to expire at the end of 2010, are not part of the revenue baseline, so extending the capital gains and dividend tax cuts requires budget cuts or tax increases of $215 billion. Paygo thus virtually guarantees a gigantic tax increase in 2011.

The key to this liberal budgeting scam is the expiration of the Bush tax cuts. For the first time the U.S. major elements of the tax code expiring. In the past, the Congress had the good sense to make (most) tax policy changes permanent. So, in the past there was little issue with the revenue baseline assuming the continuation of current tax policy because current tax policy had no expiration date. This new difference in the formulation of the revenue and spending baselines is unfair, and blatantly biased.