After months of debate over a major tax cut and with a mere three days before the bill is due on the president’s desk, the Senate discovered this week that it had accepted a miscalculation – off by a mere $70 billion – of what the dividend tax cut would cost, forgot to include language on reducing the top income tax rate and tentatively decided that a $383 billion plan was the same at a $350 billion plan. The looters of Baghdad looked thoughtful by comparison.

The fulcrum that help launch this week’s chaos was set in place by Senate Finance Chairman Charles Grassley, who announced in April that a deal had been struck, involving himself and moderate Republicans, Sens. Olympia Snowe and George Voinovich. “I agreed that I would not return from the [House-Senate] conference on the growth package with a number greater than $350 billion in revenue reductions,” Sen. Grassley said. “This means that, at the end of the day, the tax cut side of the growth package will not exceed $350 billion over the period of the reconciliation instruction” – the next 10 years.

The Finance Committee and later the full Senate then worked and reworked a tax-cut plan to fall under $350 billion, including aid to the states and a child-tax credit. Pretend end dates for the dividend tax cut and other cuts were accepted so that the entire package would not exceed the $350 billion. It was an unattractive piece of legislation but by the end of last week, there it stood, barely approved and barely under its cap.

And then this week it wasn’t. Money for the states is not a tax cut, the conference concluded, which is within the letter but nowhere close to the spirit of the $350 billion understanding. Same thing for parts of the child-tax credit. Placing those outside the Senate plan adds $33 billion to a total, which as of Wednesday evening included dividend rate reductions rather than the tax elimination – a boon for states – and sunsets on even more taxes that may not actually sunset. The acceleration of tax-rate reductions pushes the package even more heavily toward the top 1 percent of earners.

Sen. Susan Collins was properly concerned yesterday that the $20 billion in state fiscal relief would suffer much the same sleight-of-hand as the rest of the bill. She demanded to see the legislative language before it was made final and was further mindful that the dividend rate reductions could revert to the tax elimination, which would cost states billions. She is correct to ensure that states be protected under such a plan.

The fiction that the emerging conference bill meets the $350 billion cap is so strained that it is unclear that its champions can cajole enough senators into voting for it. Of the state relief, Sens. Collins and Ben Nelson said to legislative leadership, “we would respectfully ask that you share with us the legislative language … before it is finalized and announced to the public so that we can review it carefully.” It is an excellent suggestion for the entire package, which could use more review and a great deal more care.