Mr Rocard, 61, prime minister for three years until May last year, received exceptionally enthusiastic applause after speaking to a congress of the ruling Socialists in Bordeaux on Saturday. Yesterday, in a clearly stage-managed conclusion, Laurent Fabius, the party first secretary, stepped from the podium to shake the hand of Mr Rocard, then that of Pierre Beregovoy, the Prime Minister.
In his speech, Mr Rocard spoke of his 'calm assurance' that, by the next presidential elections, the party 'will be completely united when the moment comes to beat the right in 1995'. His main rival for the Socialist candidature is Jacques Delors, 67, the European Commission president. Mr Fabius, at 45, is the strongest candidate in the younger generation but his behaviour in Bordeaux indicated that he is throwing his support behind Mr Rocard as the successor to Francois Mitterrand.
Mr Delors limited his congress speech to a defence of the Maastricht treaty, ratification of which will be put to a referendum in France on 20 September. Mr Delors, 67, while respected for his work in Brussels and as finance minister before that, is less popular with many Socialist militants than Mr Rocard.
A senior member of the staff of Jacques Chaban-Delmas, the Gaullist prime minister from 1969 to 1972, Mr Delors does not have the socialist credentials of Mr Rocard, who has been firmly of the left since his student days.
The Socialists, suffering from falling popularity and, most recently, from a report last week that Henri Emmanuelli, one of their senior members and the Speaker of parliament, is to be charged in connection with illegal party funding, were meeting for the last time before the referendum, and parliamentary elections in March.
Mr Emmanuelli's plight, discovered because of a leak somewhere in the justice machine, gave the congress a cause and served to close the ranks.
But the conservative opposition is in disarray over Maastricht and is also suffering from a bad public image. Mr Beregovoy spoke of the need for new alliances to govern the country. Some analysts believe that members of the pro-Maastricht centre and right, in the Union for French Democracy of Valery Giscard d'Estaing, might be willing to serve in a coalition with the Socialists after what are expected to be bruising battles with the anti-Maastricht factions in the coming weeks.
Mr Rocard, who has the advantage of being asked to resign by President Francois Mitterrand last year as he was riding high in opinion polls and just before the government's popularity plummeted, warned against the temptation to conclude agreements before the elections.
Jean-Pierre Chevenement, the former defence minister and main Socialist anti-Maastricht campaigner, was jeered during his speech, in which he said Maastricht bolstered free-market liberalism. 'The Europe of Maastricht is the Europe of Giscard,' Mr Chevenement, who is on the left of the party, said. In a radio interview, he described the party's programme for next year's elections as 'odourless, colourless and tasteless' and designed to permit 'all possible alliances'.