Following the formal request for a prosecutor from the Democrat-dominated House Judiciary Committee, the Attorney General, William Barr, has 30 days to make a preliminary ruling. Assuming a go-ahead, he could appoint a panel to name a prosecutor 60 days after that - on 7 October, less than four weeks before election day on 3 November.
Mr Barr retains the option of a further two months delay. But a watershed in what is dubbed 'Iraqgate' has been crossed. Out of a bewildering skein of leaks and accusations has emerged the possibility that the adminstration's backing for Saddam Hussein until the eve of his 1990 invasion of Kuwait may have defied not only common sense, but the law as well.
For Republicans, the growing Iraq controversy remains what President Bush called it a week ago - 'a political witchhunt' mounted by his foes to cause maximum embarrassment at the worst possible moment. But in a television interview from Helsinki yesterday, Mr Bush was uncharacteristically muted, saying his lawyers had advised him not to comment on the issue.
Democrats meanwhile are unequivocal. The 'stupidity' of the pre-Gulf war policy 'speaks for itself', said the House Judiciary Committee's chairman, Congressman Jack Brooks. 'Even the President has acknowledged it was an utter failure. What we are concerned about is that high administration officials, in their zeal to carry out this policy and then to keep it from being exposed, may have broken the law.'
The areas of possible criminal behaviour are several, including: claims that the Commerce Department deliberately doctored a list of exports to Iraq requested by Congress after the invasion of Kuwait; that officials may have deliberately misled Congress; and that the administration knew loans to Iraq in the 1980s by the Atlanta branch of Italy's Banca Nazionale del Lavoro were being diverted into Baghdad's arms build-up.
These suspicions grew further this week when it emerged that a White House lawyer telephoned Atlanta prosecutors probing the BNL affair in 1989, pointing out the risk of embarrassment for the White House.
If Mr Barr now authorises a special prosecutor - and precedent suggests he has little choice but to do so - Mr Bush could be facing double trouble from the direction of the Gulf. For quite apart from 'Iraqgate' the far older Iran-Contra affair is again lapping at the White House.
After the indictment last month of Ronald Reagan's defence secretary, Caspar Weinberger, the Iran-Contra special prosecutor hinted that cover-up charges could be levelled at other officials from the 'most senior levels' of the Reagan adminstration. These can only be the former secretary of state George Shultz, Mr Reagan himself - or then vice-president George Bush.