Mr. Padden says AOL's interest in openness is new and corresponds to the merger review in Washington.

But his agency, which is called the Ministry of Competition, only undertakes a full-scale merger review after finding potential problems during an initial, monthlong review.

The Justice Department's decision to end the merger review will make things considerably more difficult for Oracle, analysts say.

As a consequence of that disclosure, the agency announced that it had stopped its "informal 180-day clock" on the merger review "until we have the information required to evaluate these models."

So how can the commission assess that in the terms of a relatively short merger review?

Mr. Mackey also said that the agency's definition of supermarkets in previous merger reviews had included traditional stores as well as Whole Foods and Wild Oats.

If the recent history of merger reviews means anything, probably not.

"These things take 14 months not because of any analytical merger review," said Powell.

It is the first time in 12 years of merger review by the commission that one of its merger-blocking decisions has been overturned in court.

American lawyers who are familiar with European merger reviews said that they expected the commission would be satisfied if General Electric spun off nearly 20 percent of Gecas.