Sen. Russell Long did something this year that would seem to go against nature: he returned $360,000 of campaign contributions that he could have kept. Members of Congress who were serving in 1980 are allowed to pocket all their leftover campaign monies (and pay personal income tax on them) when they retire, and many do. Mr. Long, who is not running next year, decided to return his unspent contributions. Now he can consider the pending tax bill knowing that he has received nothing from individuals or PACs with economic interests in the legislation.

That's more than you can say of the two senators who have succeeded Mr. Long as chairman of the Senate Finance Committee, Bob Dole and Bob Packwood, who are both running for reelection in 1986. In the first six months of 1985, Sen. Dole took in some $833,000 in contributions, including $474,000 from PACs; he now has the enviable total of $1.6 million cash in his campaign treasury. That is guaranteed to give pause to any Kansas Democrat who might be thinking of taking on the Senate majority leader.

As for Mr. Packwood, he raised $2.6 million in the first six months of this year -- more than any other member of Congress. Some $691,000 came from PACs. Mr. Packwood's campaign five years ago was supported in large part by individual contributors who appreciated his work as the Senate's leading opponent of restriction on abortions. His campaign next year, evidently, will be supported in large part by those seeking favor with the chairman of the Senate Finance Committee. You can make a case that an intelligent legislator with definite views on policy is not going to be unduly swayed by contributions that come from people with diverse interests on diverse economic issues; they will tend to cancel each other out, you could say, and taken together, as a spokesman for Mr. Packwood has suggested, they tend to represent the whole range of American consumers and workers. You can make that case -- but not many people with practical experience and a modicum of common sense will believe it. They will know that some interests -- typically those who benefit most generously from current or proposed laws -- will be represented most vociferously and generously; while the vast generality of people, those with an interest, for example, in simple equity of treatment of similarly situated taxpayers, may not be represented at all.

Mr. Dole has shown an adherence to principle and a suppleness of political sinew not often seen in this town, and his integrity is not in doubt; Mr. Packwood is an industrious and honorable legislator who has articulated his own views on taxes frequently. But, so assiduously seeking campaign funds when the tax bill is pending, they have not set a good political example. They have what they must consider a worthy end in view: their own reelection. But they have helped contribute to an atmosphere in which legislators, not always as scrupulous as these two, have been unashamedly raking in vast sums of money from those seeking favor from them.