German Chancellor Angela Merkel / AFP PHOTO / John MACDOUGALL Shifting tectonic plates in German politics are set to mark a second regional election in as many weeks Sunday, threatening fresh aftershocks for Chancellor Angela Merkel’s battered Berlin coalition. The capital’s government quarter has held its breath since Bavarians punished Merkel’s allies — the conservative Christian Social Union (CSU) and centre-left Social Democrats (SPD) — in a state poll earlier this month. Aiming to damp down infighting that has driven voters from the traditional big parties, leaders urged discipline and no heads rolled before polls opened at 8:00 am (0700 GMT) for 4.4 million voters in Hesse state — just seven percent of the national electorate. “Will Hessen explode the grand coalition?” in Berlin between Merkel’s Christian Democratic Union (CDU) and the SPD, top-selling newspaper Bild asked. “Hessen votes, Berlin trembles,” agreed daily Sueddeutsche Zeitung. “The chancellor has never been un...