The Atlantean Senate was the supreme legislative body of the United States of Atlantis.
History: the Atlantean Assembly and the Atlantean War of Independence
The Senate began as the Atlantean Assembly, established in 1774 as a congress of representatives from all across Atlantis, representing the English-speaking areas as well as the French region. It was created after the failure of the settlements to individually petition Britain, with the hope that a great single voice would be listened to. As they feared they were generally ignored.
The Assembly was almost powerless. It could only pass its resolutions by two-thirds vote, but the resolutions weren't binding. It couldn't tax, but had to ask for money instead. It wasn't quite the Polish liberum veto, as Radcliff thought, but it came close.
The Assembly's first capital was in New Hastings, but was forced to evacuate to the northwest after General Howe's British army defeated Radcliff's army in a grinding campaign. The Assemblymen set up their new seat of power in a rented room in the backwoods hamlet of Honker's Mill.
After the Treaty of Croydon was signed in 1778, the Assembly made some adjustments to the federal system of government in Atlantis, giving executive power to two consuls as well as renaming itself the Atlantean Senate.