The Conservatives, as a Britain-wide party, fielded candidates in Scotland until the creation of a separate Unionist Party in 1912. This was a separate party which accepted the Conservative whip in the UK Parliament until it was merged into the Conservative Party in 1965. The Declaration of Perth policy document of 1968 committed the Conservatives to Scottish devolution in some form, and in 1970 the Conservative government published "Scotland's Government", a document recommending the creation of a Scottish Assembly. Support for devolution within the party was rejected and was opposed by the Conservative governments led by Margaret Thatcher and John Major in the 1980s and 1990s. The party largely remained opposed to devolution in the 1997 Scottish devolution referendum campaign. That referendum was passed with a large majority, the Conservatives have since accepted devolution in both Scotland and Wales. The governments led by David Cameron devolved further powers to the Scottish Parliament in 2012 and 2016. Cameron also attempted to answer the "West Lothian question" by changing the procedures of the UK Parliament (English votes for English laws).