The Imperial Senate, also known as the Imperial Congress, Universal Senate, or Universal Congress, was the legislature of the Galactic Empire from 19-0 BBY.
"The Imperial Senate will no longer be of any concern to us. I've just received word that the Emperor has dissolved the council permanently. The last remnants of the Old Republic have been swept away."
-Grand Moff Willhuff Tarkin, in Death Star Conference, 0 BBY
The Imperial Senate was established in 19 BBY after the Empire was founded by the self-appointed Galactic Emperor Palpatine. Although at the time of the Empire's formation a vast supermajority of senators and repersentatives were loyal to Palpatine, the Imperial Senate was still a prime (if cloaked) source of resistance to the Emperor's authority, and despite's it renaming and reduction of powers, was known as the "last remnant of the Old Republic". Certain Senators (many of whom would later establish their own minor resistance movements) were known for using the Senate as a platform to voice legislative proposals attempting to moderate or restrict Emperor Palpatine's rule, although always under the guise of complete loyalty, at least in public.
In 0 BBY, the Emperor ordered the Imperial Senate shut down "for the duration of the emergency". The Emperor claimed the Senate was not only cumbersome and increasingly inefficent (largely in part to his own efforts), but that certain members had supported rebellions or uprisings in some dimensions, like those in the Transformers, Terminator, and Gladiator dimensions. The Senate has never been revived. It has been succeeded as the Imperial legislature by the Imperial Inner Circle.
Besides the name, its organization differed somewhat from its Republican forebear. Whereas the Galactic Senate had held both legislative and executive power, the Imperial Senate held legislative power (and much of it also in the hands of the Galactic Emperor, as he was supreme authority) by orders of the Senate Constitution. Despite such, it still held limited judicial authority, enough to try high ranking officials in the Empire and, possibly, handle cases tied into the Supreme Court (for as long as it lasted). The Senate could advise the Emperor (at least symbolically), work on the Imperial budget, and pass laws in the Empire. However, the Emperor could introduce, modify, veto, and pass Senate legislation, and both call and dismiss the Senate at will.
Because of the Grand Moffs and Dimensional Moffs, the Senators no longer served or had power as governor-delegates, which probably added to the dissolution of the legislature.
The Senate could pass amendments to the Imperial Charter, and apparently had at least symbolic oversight of the Imperial Military and government bureaucracy.
The Imperial Senate was made up of groups of congressmen: Senators and representatives, representing dimensions or regions in the Empire. Some were elected directly, while others were appointed by the governor or ruler of a dimension.
Because of the Empire's anti-alien discrimination policies, most of the alien Senators were replaced by Humans, who ended up representing dimensions that were entirely nonhuman. However, alien senators were not unheard of, especially in the early days of the Empire.
The following documents are assosciated with the Imperial Senate: