''Big-time Clinton-Gore donor Ted Sioeng,'' wrote The Wall Street Journal's crusading editorialist, ''poured some $250,000 into campaign coffers, and has recently been on the lam from nosy investigators.''

On the lam means ''running away'' or ''being a fugitive from the law''; bureaucrats would say ''in escape status.'' The origin of the expression is in heated dispute among slang etymologists.

In The Random House Historical Dictionary of American Slang, J.E. Lighter defines the term as prison lingo for ''an act of running or flight, esp. a dash to escape from custody.'' In his 1886 ''30 Years a Detective,'' Allan Pinkerton, the first ''private eye,'' explains an operation of pickpockets: ''After he secures the wallet, he will utter the word 'lam!' This means to let the man go and to get out of the way as soon as possible.'' Lighter cites do a lam, make a lam and take a lam early in this century, finally emerging as the passive state of being on the lam.

Lighter speculates that it may be rooted in the dialect Scandinavian verb lam, as in the 1525 ''his wife sore lamming him,'' meaning ''to beat, pound or strike.'' Mark Twain used it twice: ''lamming the lady'' in 1855 and ''lam like all creation'' in 1865, both clearly meaning ''to beat.'' The suggested connection is that to avoid a feared lamming (related to slamming), one lams.