First, the slogan was "privatization" -- the sale of government assets. Now it is "tax amnesty." An era of oppressive federal deficits always produces innovative gimmickry designed to avoid more painful ways, such as tax increases, to stem the flow of red ink.

We had a classic example of this in the president's budget message, which prettied up the real deficit by $7 billion for fiscal 1987 by the proposed sale of physical and financial assets. Through a process of "privatization," Reagan called for the sale of the Bonneville Power and other regional power agencies, the Naval Petroleum Reserves at Elk Hills, national weather satellites and other valuable assets.

My mail in response to an earlier column challenging the assumption that private industry can always outperform the public sector indicates that many average citizens are outraged at the effort to transfer public wealth represented by land and dams and other investments into private hands. Legislators who would put private profit above public welfare had better run scared in the next election.

Now, on top of "privatization," comes tax amnesty, another piece of mischievous nonsense in the desperate scramble to find ways of reducing the budget deficit, while honoring Reagan's knee- jerk opposition to any form of higher taxes.

Stimulated by the apparent success of amnesty programs in several states, including New York, Massachusetts, California and Illinois, members have introduced at least 13 amnesty bills in Congress. Treasury Secretary James A. Baker III recently told the Joint Economic Committee that the proposals are "very much worth considering," and House Speaker Tip O'Neill says amnesty is "a good thing."

But the peoplwho know most about tax collection -- such as IRS commissioner Roscoe L. Egger Jr. and former commissioners Mortimer Capposed. They scoff at guesses that forgiving tax cheaters could produce anywhere from $10 billion to $25 billion in a one-time coup for the Treasury.

Egger, in congressional testimony, cited a number of "serious" drawbacks, among them that one amnesty program "might encourage the belief that the offers would be repeated in the future, leading to noncompliance in the interim."

Honest taxpayers, he said, "may perceive an amnesty as 'special treatment' for dishonest taxpayers, and therefore unfair, inequitable and contrary to IRS's policy of administering the tax laws uniformly."

In Caplin's view, a federal amnesty program would undercut the very core of the present tax system, which is based on voluntary self- compliance. "Over 97 percent of what we collect comes from voluntary compliance, and with all of the beating of the bushes, we get barely 3 percent," Cap

The most publicized of the amnesty bills is S. 203, introduced last year by Sen. Alan J. Dixon (D-Ill.) and cosponsored by Sens. Alfonse M. D'Amato (R-N.Y.), Daniel P. Moynihan (D- N.Y.) and John F. Kerry (D-Mass.).

This bill provides for a one-time, six-month amnesty period in which a taxpayer who confesses that he cheated would have to pay only the taxes he owes, plus 50 percent of the interest, to be relieved of all civil and criminal penalties.

Caplin points out that until the Reagan administration showed new interest in the amnesty gimmick, the traditional Treasury position had been that amnesty is a flawed approach.

As recently as June 24, 1985, Treasury Deputy Tax Legislative Counsel Dennis Ross, speaking for the Treasury, said at hearings on S. 203: "We should not enact taxpayer amnesty at the federal level. Our conclusion is based principally on concerns over the actual and perceived fairness of a federal amnesty program, and thus over the possible adverse effects of an amnesty program on taxpayer morale and compliance.

"In addition, we question whether an amnesty program would raise significant revenue in the short run, and indeed, we are concerned that amnesty would be a long-run revenue loser."

Caplin says that the successful results in a few states do not necessarily translate to the federal system. For example, Massachusetts expected to pick up $20 million in an amnesty experiment in 1983 and actually collected four times that amount. But unlike the federal government, Massachusetss never had had an efficient tax collection and enforcement system. For the first time, as Massachusetts launched its amnesty program, it cracked down on tax cheaters and made tax evasion a felony.

Better, Caplin says, not to scrimp on the federal budget for IRS: austerity has cut the number of federal audits to little more than 1 percent of the returns, compared with 5 percent 20 years ago. "Give them the resources to do their job," Caplin says. It's good advice, and Congress ought to heed it.