WHEN FRIEDRICH MERZ takes office as the tenth chancellor of the German Republic on May 6th, it will mark the culmination of a winding journey full of missteps and tumbles. So often the nearly-man of German politics, the 69-year-old Mr Merz has made no shortage of enemies over his long career—none greater than himself. The centrist coalition he has negotiated will begin its work amid economic and geopolitical tumult, and will be led by a man whose own character makes his approach to the job difficult to predict.