Internationally, Cameron's government intervened militarily in the First Libyan Civil War and authorised the bombing of the Islamic State of Iraq and the Levant. Domestically, his government oversaw the referendum on voting reform and Scottish independence referendum, both of which confirmed Cameron's favoured outcome. When the Conservatives secured an unexpected majority in the 2015 general election, he remained as prime minister, this time leading a Conservative-only government. To fulfil a manifesto pledge, he introduced a referendum on the UK's continuing membership of the EU. Cameron supported continued membership; following the success of the Leave vote, he resigned to make way for a new prime minister and was succeeded by Theresa May. Cameron has been the President of Alzheimer's Research UK since 2017.