The Vandalia Council was the legislature of the Confederation of Vandalia. Unlike the original five confederations of the Confederation of North America, Vandalia was not created under the Britannic Design of 1781. Instead, it was formed out of territory conquered from Spain during and after the Trans-Oceanic War of 1795 - 1799.
Sobel has little to say about the creation of Vandalia, including any transition period from its status as occupied Spanish territory to the establishment of the Confederation of Vandalia, except to note that the new confederation had been established by 1810, at which time it had only 2,000 white settlers. The capital of the new confederation was presumably located in its largest settlement, St. Louis. Given that a majority of its settled inhabitants would have been former Spanish and French settlers, it is unknown whether a popularly-elected legislature was immediately established. Once a sufficiently high number of North Americans had settled in Vandalia, the Vandalia Council would have been organized to serve as their government. Among its other duties the Vandalia Council would have chosen the Governor of Vandalia from among their number. After passage of the Second Britannic Design in 1842, the Governor of Vandalia would also have been popularly elected.
Sobel makes no mention of any actions taken by the Vandalia Council, but it is likely that a majority of the Council voted in favor of the separation of Vandalia into two parts in the 1870s. Based on Sobel's tally of the councils of the two daughter confederations, it appears that the partisan makeup of the last session of the Vandalia Council was 75 Conservative Party members, 43 Liberal Party members, and 11 People's Coalition members.