In foreign policy, Merkel has emphasised international cooperation, both in the context of the European Union and NATO, and strengthening transatlantic economic relations. In 2007, Merkel served as President of the European Council and played a central role in the negotiation of the Treaty of Lisbon and the Berlin Declaration. Merkel played a crucial role in managing the global financial crisis and the European debt crisis. She negotiated a stimulus package in 2008 focusing on infrastructure spending and public investment to counteract the Great Recession. In domestic policy, Merkel's "Energiewende" program has focused on future energy development, seeking to phase out nuclear power in Germany, reduce greenhouse gas emissions, and increase renewable energy sources. Reforms to the Bundeswehr which abolished conscription, health care reform, and more recently her government's response to the 2010s migrant crisis and the COVID-19 pandemic in Germany have been major issues during her chancellorship. She has served as senior G7 leader since 2014, and previously from 2011 to 2012. In 2014 she became the longest-serving incumbent head of government in the European Union. In October 2018, Merkel announced that she would stand down as Leader of the CDU at the party convention, and would not seek a fifth term as Chancellor in 2021.