Political parties in Northern Ireland supporting maintenance of the union with the UK. In 1886 Lord Hartington and Joseph Chamberlain formed the Liberal Unionists, allying with the Conservatives and pledging to maintain the Union of Ireland with the rest of the United Kingdom. In 1920, with the division of Ireland, the majority party in Northern Ireland was the Unionist wing of the Conservative Party, now calling itself the Ulster Unionists, under Sir James Craig, who was Prime Minister (1921–40). The party, supported by a Protestant electorate, continued to rule under his successors, until the imposition of direct rule from Westminster in 1972. The increased violence between Nationalists and Unionists after the civil rights campaign of 1968 led to divisions in the party, and in 1969 it split into the Official Ulster Unionist Party and the Protestant Unionist Party. The latter, established by the Revd Ian Paisley, was renamed in 1972 the Ulster Democratic Unionist Party (DUP), and led by Paisley until 2008, by Peter Robinson until 2015, and then by Arlene Foster; it has generally followed policies more extreme than those of the Ulster Unionists (led from 1979 to 1995 by James Molyneaux, from 1995 to 2005 by David Trimble, from 2005 to 2010 by Sir Reg Empey, from 2010 to 2012 by Tom Elliott, from 2012 by Mike Nesbitt, and from 2017 by Robin Swann). Support for the Ulster Unionists collapsed from 2005, which left the DUP as the leading unionist party. Since 2007 the leader of the DUP has been First Minister of Northern Ireland. Following Assembly elections in 2017 the DUP had 28 seats while the UUP were down to 10; the UUP had left the power-sharing executive in 2016 to become an opposition party.