The Dissolution of the Imperial Senate was the official suspension of the Imperial Senate by order of Emperor Palpatine in 0 BBY.
From the beginning of the Galactic Empire, Palpatine sought to remove the Senate. The first reason was symbolic: he could not leave a reminder of the Republic. It was known as the "last remnant of the Old Republic". The second was political: some senators still opposed him. His obedient majority tried keeping them in check; they understood they were only there to prop up the illusion of democracy. Some, however, didn't understand the sham; they actually tried passing laws against the Emperor's wishes. He dealt with the outspoken ones when they appeared, but like weeds others sprouted in their place. Some of them, as Palpatine suspected, were providing resistance movements, in numerous dimensions (such as Transformers, Terminator, Gladiator, Titanic, and Harry Potter), with funds, information, and military resources.
After learning that Senator Connaught Rosa of the Star Trek dimension was a member of a resistance cell in that dimension, the Emperor issued the dissolution of the Senate, via the Grand Convocation Chamber of the Senate Building on Imperial Center (Coruscant). Palpatine claimed that if resistance movements gained great support in the "high organs of the Imperial Government", that the Empire would implode upon itself. The Emperor then claimed the Senate's dissolution would only last until the Empire's rule was consolidated unchallenged. However, this was a lie. Dimensional and Regional Governors were assigned direct control of their dimensional territories.
Warrants were issued for the arrest of all suspected Resistance members. Stormtroopers burst into the Senate Building, and thousands were detained. Some-those learned to have supported or had sympathies for any minor Resistance cells-were never seen again. The following morning, the remaining senators-unaware of what had happened-came to work only to find themselves locked out of their own offices and chambers. Some tried to appeal to Emperor Palpatine directly, but were informed that their diplomatic access to the Imperial Palace had been suspended "for the duration of the emergency".
Many who were released left Coruscant for their homedimensions, and a peaceful—and isolated—retirement. The small number of senators that remained, the ones who had most voraciously upheld the party line, were generously rewarded with their lives and new positions. Many of them have donned ornate jeweled robes and joined the swelling ranks of Imperial advisors.
Though it was claimed that the dissolution was temporary, only the most deluded of people have actually believed the Emperor's statement. A new pyramidal structure has been imposed, with Emperor Palpatine himself at its summit, then the Grand Moffs who rule the Oversectors, then the Moffs who rule the dimensions, then the governors of individual worlds or sections. All of them owe their careers to the Emperor and give him their allegiance.
The end of the Senate has left the field wide open for COMPNOR to step in. For all the power of the Moffs, COMPNOR stands behind them, more powerful still. In the absence of the Senate, Palpatine has established an environment where even his subordinates were capable of terrible atrocities against sentient beings. Behind them all is the Death Star, a weapon that is used to incite fear and terrorize those unfaithful to the New Order.