(FORTUNE Magazine) – Dear Numerocruncher: My paleoconservative discussion group on the Internet has lately focused on the unusual number of solons opting for retirement this year. The most interesting case by far is one of the eight departing Senators, Majority Leader George J. Mitchell of Maine, arguably the leading liberal menace in Washington. George has twice stunned the Beltway in 1994: first when he announced he would not run for reelection this fall, preferring instead to ''consider other challenges,'' next when he said he could not possibly be a candidate for the Supreme Court as this would get in the way of his labors on behalf of the Clinton health plan. Not surprisingly, the lightweight liberal media swallowed Mitchell's story line with scarcely a burp. Sob sister Mary McGrory of the Washington Post wrote tremulously that he ''had put the moral imperative of health care above his career advancement.'' What a guy, eh? And yet our own less weepy chaps have sensed that Mitchell's exposition must be incomplete. How could we not think so after all our on-line chortles over the gibe of Senator Phil Gramm of Texas (American Conservative Union rating: 93), who keeps asking what is the difference between Elvis and the Administration health plan? The answer is that the former might be alive. And now we think we know what is really what with Mitchell. The true story was told not in the Post but in Human Events, Ronald Reagan's favorite weekly. In the May 27 issue, our spiritual guides at this publication posit that Mitch's itch is pecuniary. Citing data published by the National Taxpayers Union, the editors note that when he leaves the Senate, Mitchell walks off with ''one of the biggest pensions in government history.'' Had he stayed on, or gone to the Supreme Court, latching on to this loot would perforce have been deferred indefinitely. Hoping that the science of statistics can further illuminate this analysis, I remain, YOUR PAL IN RIGHT WINGERY

Dear Paleo: The taxpayers and Ron's weekly are definitely on to something, as evidenced by certain details: (1) Mitchell's retirement comes exactly three years after the Senate pay raise of 1991, which George fearlessly co- sponsored. (2) The raise resulted in his pay as majority leader spiraling upward from $113,400 a year to $148,400 today. (3) Although participants' names are not in the public record, he is almost certainly in on the wonderfully generous congressional pension plan, which (4) offers annual payments of 2.5% of the average of the three highest years' pay for each year of legislative service. Like the seven other Senators retiring this year, Mitchell is latching on to a pension bonanza based on that 1991 raise. Upon retiring from government, he will be able to collect an annual pension of $84,595, and based on his age, race, and sex, he has a life expectancy of 22 years. Since the pension is of course indexed (unlike 90% of private pensions), a 4% inflation rate over those years would leave him collecting a total of $2,895,248. An additional marvelous detail mentioned by Human Events is that George (a widower) has a 35-year-old fiancee who would be able to collect 55% of his pension during the 27 additional years she is actuarially entitled to live. A pension in which she participated would generate total payments of $7,808,529 over the years. Net present value of the payments at a 7% discount rate: $1,629,148. This is of course on top of whatever the guy makes as Commissioner of Baseball, the job he obviously wants. In recent years the job has paid about $1 million a year, not counting pension benefits. Talk about ''other challenges.''