The SPD held its meeting on Saturday in Dortmund, with party head Sigmar Gabriel getting delegates into the campaign mood by calling Christian Democratic Chancellor Angela Merkel trivial, her Free Democrat deputy Guido Westerwelle radical, and praising the state of North Rhine-Westphalia.
The SPD candidate, Hannelore Kraft, was greeted with huge applause from supporters waiting to see her take on Christian Democratic Union state premier Jürgen Rüttgers.
He has been badly damaged by a scandal in which his fellow party members were found to be selling meetings with the premier at last year's party convention. The CDU general secretary in the state, Hendrik Wüst, resigned last week over the affair after it was revealed that he had charged €6,000 for personal discussions with Rüttgers.
A survey published in the Bild am Sonntag showed that only 11 percent of participants believed the premier had no knowledge of the fund-raising tactic.
Although things are looking up for the SPD, it will need a coalition partner to take over in North Rhine-Westphalia. Gabriel said only the environmentalist Greens would be suitable, dismissing the option of working with the socialist Left party.
The May 9 state election is the only one this year, and could affect the balance of power in the upper house of parliament, the Bundesrat. If the CDU loses the election, Merkel's centre-right coalition would no longer have a majority in the chamber, and would find passing laws more difficult.