The SDLP is the Social Democratic and Labour Party, a political party in Northern Ireland. Most of its support has come from Catholics. It sits on the centre-left: it wants a fairer society, and it also wants Northern Ireland to become part of the Republic of Ireland one day. The important messy truth is this: unlike some other nationalist groups in those years, the SDLP said you must not use bombs or guns to get there. It played a real part in the peace talks of the 1990s that tried to end the long conflict known as the Troubles. If you see SDLP in a story about Belfast, John Hume, or the Good Friday Agreement, that is the party — nationalist in its long aim, but firmly against violence as the method.