(FORTUNE Magazine) – Dear Mr. Statistics: At present the U.S. has four living ex-Presidents -- Richard Nixon, Gerald Ford, Jimmy Carter, and Ronald Reagan -- but four is not the record. There was a time when our nation had five of those guys still breathing regularly, enough for a decent poker game, although there is no evidence that Martin Van Buren, John Tyler, Millard Fillmore, Franklin Pierce, and James Buchanan ever got around to playing. Unfortunately, this quinary situation lasted a mere 10 1/2 months, at the end of which Tyler died (January 18, 1862). My registered Democratic question is, What are the chances of tying the five-man record in the months ahead so we can finally get that game launched? -- NOT BLUFFING THIS TIME

Dear Not: For the U.S.A. to tie the record, six things must happen: Bush has to lose the election, he must survive until Inauguration Day (January 20, 1993), and so must Dick and Gerry and Jimmy and Ron. In ascertaining the probability of George's losing the election, we dismiss all polls and turn instead to a market-driven predictor in which people back up their judgments by putting down their own coin. One good market is in Britain, where betting on U.S. presidential elections is legal and a betting line is maintained by the major bookmakers. At the beginning of September, London's largest bookmaker, Ladbroke's, was quoting odds that translated (after adjustments to eliminate the house vigorish) into a 62.5% probability of a Bush defeat. Next question: What is the probability that all five of our aging gents will make it to Inauguration Day? Based solely on actuarial data on white males supplied by the National Center for Health Statistics (and ignoring all rumors about any particular individual's health status), we note that each of the five is a heavy favorite to survive another 4 1/2 months; Reagan, the oldest of the group, would have a 98.8% chance of doing so. The probability of all five surviving would be 94.9% Multiplying that figure by the 62.5% chance of Bush's losing on November 3, we come to a bottom line showing a 59.3% chance of the country's again having five living ex-Presidents.

If they play poker, those other guys had better watch out for Nixon, whose finesse at the game is documented in Roger Morris's biography, Richard Milhous Nixon: The Rise of an American Politician, which says that in his Navy years R.M.N. once bluffed a lieutenant commander out of a $1,500 pot with a pair of deuces in five-card stud.