WHAT'S SO wrong with asking people to pay their taxes? Senate Finance Committee Chairman Robert Dole posed that question the other day to leaders of the American Bankers Association. It's a question that needs a much better response than the campaign of obfuscation and hysteria launched by the bankers in opposition to the new law requiring partial withholding of taxes on interest and dividends.

The bankers know full well that the new law will put no burden on any honest taxpayer. No one is being asked to pay anything he does not already owe. People who are elderly or have modest incomes are exempt. The interest lost from quarterly withholding of taxes would amount to a maximum of 50 cents a year on a deposit of $1,000. Would that bank service charges were so low.

But protesting bankers also know that it is easy to confuse people about tax law changes. So instead of preparing to put the law into effect, they have bought ads, given speeches alleging that Congress is "looting" savings, and mailed misleading fliers to their depositors with form letters to congressmen enclosed.

Like most such tactics launched upon an uninformed and frequently elderly public, these have had their effect. The form letters have poured in to Congress. A substantial number of senators and representatives--who, alas, are frequently no better informed than their constituents--are said to be considering repealing the withholding provision.

What prompts this disingenuous behavior? Surely no real concern for the convenience of depositors. As a matter of fact, bankers opposed the exemption provisions for elderly and low-income people when the law was being drafted. What they really appear to be worried about is their own convenience--and the prospect that withholding might scare off depositors with an inclination to tax evasion.

Banks already send quarterly information forms to the IRS on all dividends and interest. Accompanying them with a 10 percent fund credit would amount to no more than the electronic equivalent of the flicker of an eyelash. The cost would be minuscule compared with the cost of having the IRS track down and collect from each of the distressingly large number of tax evaders. But the banks would still have you believe that this new chore would cost them and their depositors, as it is regularly said, "untold billions."

But the thing about untold billions is that the usual reason they are untold is that telling them would require using numbers with several zeros immediately to the right of the decimal point. Somehow a number like $.001 billion has a lot less impact. But speaking of untold billions, you might want to remember that these bankers who now claim to be so concerned about prudent operation are the same ones who have been recklessly investing overseas and who would now like to have government protection from the consequences of their folly. Here the billions involved are more unspeakable than untold--and certainly uncollectable.

You might also remember, as Sen. Dole has done, that banks now pay notoriously low taxes. If Congress unwisely decides to repeal the withholding provision, one very good way to replace the $22 billion in unpaid taxes that will be lost over the next five years would be to repeal some of the provisions that now favor banks over other taxpayers.