American Lutheranism arrived in national fragments, organised by the country and the synod its immigrants came from, and the twentieth century was largely spent consolidating them. The merger of 1988 was the culmination. The American Lutheran Church, with roots in Norwegian, Danish and German immigration and its strength in the upper Midwest, and the Lutheran Church in America, with Swedish, Finnish and Pennsylvania German roots and its strength on the east coast, were the two large partners.
The third partner was small and its presence changed the character of the result. The Association of Evangelical Lutheran Churches was formed in 1976 by congregations and faculty that had left the Lutheran Church Missouri Synod after a conflict over biblical scholarship, in which most of the faculty of the Missouri Synod seminary in St Louis walked out and continued teaching in exile. Bringing that group in signalled where the new church would stand on the questions that had produced the split.
The resulting body is organised into synods, each with a bishop, under a churchwide assembly and a presiding bishop, and it holds the Book of Concord as its confessional standard. It ordains women, which it inherited from both large predecessors. It is the largest Lutheran church in the United States and, like most historic American Protestant denominations, has been losing membership for the whole of its existence.