German leader Angela Merkel faces a tricky test at the ballot box tomorrow, in regional polls seen as setting the tone for next month’s general election.In Thuringia and Saarland, her conservatives look sure to win the most votes but could still be ousted if rivals form alliances. In Saxony, the Chancellor can be more confident her CDU will retain power. On the campaign trail, Merkel backed Thuringia’s state premier Dieter Althaus. He is hoping to keep his job despite being convicted of manslaughter by negligence after a ski-ing accident in which a woman died and he himself suffered serious head injuries. With virtually no chance of replacing Merkel as Chancellor, if opinion polls are to be believed, her main challenger and Foreign Minister in the current grand coalition government has also been campaigning for the state votes. Frank-Walter Steinmeier’s Social Democrats’ best chance of power in Thuringia could be to join forces with the far-left “Linke” party which leads his SPD in voter surveys there. Losing two state governments could rattle nerves for Chancellor Merkel – creating a setback in her so-far almost effortless bid to secure a second term.