The WELS Protest Committee was "called into existence through [an] election by the General Synodical Committee in October, 1956, pursuant to a resolution of Joint Synod in August of 1956."
Here is their first report to the convention in 1957.
1957 A Report from the Protest Committee (WELS proceedings, p. 146-148)
Quotes of note:
"... nor let it be forgotten that in resolutions of earlier conventions our Synod did speak the kind of language concerning the gravity of the issues involved and concerning the interpretation and application of Romans 16:17,18 which gave the protesters reason to expect final action at Saginaw."
"... yet we would plead that hte protesters in charity trust that there was an honest uncertainty at Saginaw concerning Missouri's having received ample opportunity in convention assembled to react to the testimony which our Synod had given since Missouri's 1953 convention..."