Donald Dewar was selected for the seat Glasgow Garscadden by a majority of three, after Dewar's friend in the Amalgamated Union of Engineering Workers MP Willie Small died unexpectedly. He was returned to parliament at a by-election on 13 April 1978, a crucial victory which was seen as halting the rise of the Scottish National Party. In Scotland's first referendum on devolution, held in March 1979, he campaigned for a "Yes" vote alongside the Conservative Alick Buchanan-Smith and the Liberal Russell Johnston. Though they won a narrow majority, it fell short of the 40% required, contributing to the downfall of the Callaghan Government, in May 1979.