Germany’s political crisis has deepened with the news that veteran conservative Edmund Stoiber will not be joining the grand coalition. The CSU leader said he would stay in his stronghold of Bavaria and that his decision was final. The move leaves chancellor-in-waiting Angela Merkel in a weaker position. Stoiber is a heavyweight and one of her closest allies.There is press speculation he may have fallen out with Merkel over the way she has designated portfolios to her would-be ministerial colleagues from the CDU. The Social Democrats are also in trouble. Chairman Franz Muentefering said he would not stand for re-election this month after party members rejected his ally for the key post of general secretary and voted in a young left-winger instead. As it is rare for a cabinet not to have a party chairman, this means Muentefering is less likely to join the coalition government. That would weaken both the SPD, for whom Muentefering has been a key unifying figure amid much factional infighting, and for Merkel, who sees him as a pragmatic centrist she could do business with.