ELCA began in Pietism, with H. M. Muhlenberg, graduate of Halle University. Oddly enough, he was sent over to counter the efforts of Zinzendorf, who did some missionary work in America under an assumed name. (Parallels to Church and Chicanery noted. They hide their work too.)
Muhlenberg's work evolved into the General Synod and the seminary at Gettysburg, Pennsylvania. The break causing the General Council (confessional, liturgical) erupted over the acceptance of a blatantly anti-confessional, Pietistic sub-synod, the Franckean.
The Pietistic General Synod was known for being anti-liturgical, anti-confessional, but very much in favor of revivals. One famous General Synod veteran (the first Lutheran professor at Yale Divinity) remembered the Mourners' Bench at his father's church, where people went forward to publicly bemoan their sins, a key part of revivalism. Billy Graham's Crusades and Pentecostal churches have used the same technique.
Pietism starts with an emphasis on outward works and emotions, so the movement is inherently vulnerable to rationalism.
ELCA's constant drumbeat against historic Christianity is typical of Pietism in the later generations. "Service unites, but doctrine divides."
The ELCA assembly has a motto that reminds me of Pietistic appeals - "God's Work, Our Hands." It is all up to us. God has no hands but ours, no feet but ours, no money but ours. When the efficacious Word in the Means of Grace is repudiated, God is in a state of paralysis without us.
ELCA is using the old TALC theme of "The Bible Book of Faith," which provided a smokescreen for the 1960 attack on the inerrancy of the Bible. The campaign worked.
