German Chancellor Angela Merkel was first elected in 2005, making her the longest-serving leader in the European Union. Her party, the Christian Democratic Union, is the major party of the country's centre-right, although the nature of German politics means coalition governments are common. In leading her party to three election victories, Merkel has developed a reputation for pragmatism and resolute but low-key leadership. Within Europe, she has been a committed proponent of greater integration and cooperation, while also emerging as one of Russian President Vladimir Putin's most staunch geopolitical opponents. Perhaps the greatest test of her leadership came during the European refugee crisis, when she elected to open Germany's borders, despite significant backlash. Upon Donald Trump's election as US president, many of trump's critics suggested Merkel had become the new "leader of the free world".