BERLIN (Reuters) - Germany’s left-leaning Social Democrats (SPD) believe September’s federal election could allow them to form a government without the conservatives, who will no longer be led by retiring chancellor Angela Merkel. Her Christian Democratic Union (CDU) suffered record defeats in twin regional votes on Sunday, already missing the “Merkel bonus” she has brought the CDU and their Bavarian CSU sister-party in four consecutive national election victories. “It is possible to govern Germany without the CDU/CSU being in government. That message is now firmly in place,” the SPD’s candidate for chancellor, Finance Minister Olaf Scholz, told a news conference on Monday. CDU leader Armin Laschet said Sunday’s result was “disappointing” for his party, and a signal that the government must do better at managing the effects of the coronavirus pandemic. The CDU’s losses in the southwesterly automotive hub of Baden-Wuerttemberg opened the way for a potential regional alliance of SPD, liberal Free Democrats (FDP) and Greens, dubbed a ‘traffic light’ coalition after the parties’ colours. In neighbouring Rhineland-Palatinate, which also voted on Sunday, a traffic light coalition was already in power before the election, and could govern again. “I think a traffic light (coalition) is conceivable at the federal level,” SPD General Secretary Lars Klingbeil told the broadcaster Phoenix. “We now need an alliance for the future in this country, and I think that’s possible with the FDP.” The business-friendly FDP, emboldened by gains in Baden-Wuerttemberg, would not be drawn on its potential as kingmaker in a national government. FDP general secretary Volker Wissing, also economy minister in Rhineland-Palatinate, told the broadcaster ARD that his party wanted to be in government, but that the regional result did not automatically translate into a federal one. Slideshow ( 4 images ) CDU leader Laschet said a “traffic light” coalition at national level was perhaps “the only hope” for the SPD, adding: “I don’t think that’s the main goal of the Greens and the FDP.” UNEASY ALLIANCE Merkel’s CDU/CSU conservative bloc has ruled at federal level for almost eight years in a “grand coalition” with the SPD - an alliance of post-war Germany’s historically dominant parties that the SPD has seen as a necessary evil in which it comes off second-best. For its part, the CDU/CSU bloc would find the FDP a much more natural partner at national level, but opinion polls indicate it currently lacks the support for such an alliance. The FDP’s inclusion in a post-Merkel government would be likely to limit flexibility to continue the deficit spending that the coronavirus pandemic has triggered, and complicate efforts to expand joint borrowing on a European level. In a national survey by the pollster Forsa published on March 10, the conservative bloc had 33% support, the left-leaning environmentalist Greens 18%, the SPD 16%, the far-right AfD 10% and both the FDP and the far-left Linke 8%. The fractured electoral landscape could open up national scenarios such as a CDU/CSU tie-up with the Greens, a “traffic light” coalition, or an alliance of CDU/CSU, Greens and FDP. Although the Greens extended their regional lead in Baden-Wuerttemberg, their co-leader Robert Habeck said they would go into the federal election as underdogs, adding that it was “absurdly too early” to discuss whether a traffic light coalition would be the best option at national level.