THE SENATE tax bill will not help with one

nagging problem of tax enforcement: the mismatch between the IRS and behemoth corporate taxpayers with their unfathomably complex returns. The mismatch may cost billions in lost revenues.

Imagine you are a very senior revenue agent, with a college degree in accounting, many years of experience and specialized training in some particular area of taxpayer chicanery, like depeciation or pension plans. You and 20 or so colleagues are assigned to the IRS's leased office space at the headquarters of a multinational corporation with 82 subsidiaries and $15 billion in assets (as near as they can tell, anyway). All of you will spend the next two years playing with computers and examining selected issues in, say, tax years 1979-81. You are confident of finding tens of millions of dollars in deficiencies. But who trembles? You, the GS-13, or they, the field marshals ahead of batallions of accountants and lawyers?

IRS assigns live-in revenue agents to the extremely large corporations, and we do not doubt that they earn their pay many times over. Using sophisticated teams to audit just 1,500 large corporations, most with assets over $250 million, the IRS found $4.33 billion in deficiencies last year--a bit more than Interior's budget; much more than that of Commerce, State or Justice. And IRS expects to collect about half of these corporate underpayments through agreements, not litigation.

But there is a lot more gold in them thar hills. Yes, we have over 17,000 IRS auditors and agents already. Still, there are apparently billions of dollars sitting around in corporate coffers available for the asking. It takes more resources to be able to ask the questions, because these companies don't know themselves what their "true" tax liabilities are. They have been so successful at lobbying for assorted intricacies in the tax code that filing and auditing their returns have become a multibillion dollar guessing game.

True, no one wants a tax collector's police state; what is wanted (and needed) is voluntary compliance. But the 90 percent compliance rates for large corporate taxpayers, while higher than for individuals, are still worse than the welfare error rates.

In recent years, the IRS has become much more sophisticated and professional. Congress should give them more than slingshots to go after the Goliaths.