Well, by stating he was the senate, all previous senators ceased to exist; their bodies turned to dust, and Palpatine gained their strength, knowledge, and overall energy/power. However, most were simply senators, so his power level didn’t increase significantly.

He had them imprisoned for crimes against the Empire. So basically jailed for trying to disagree with the emperor.

Palpatine received all of the Senate’s power during Attack of the Clones, and when he had their trust, he transformed the Republic into the Empire and most people couldn’t see what he was planning until it was too late. Palpatine disbanded the Senate in A New Hope because he had fear at his side with the Death Star. Any system that now rebels against his empire would be destroyed and the other systems would know where there place is.

Yes, he only had the senate because he knew if he turned his empire into an absolutism state, many planets would rebel against him. So he built the death star, to ensure nobody would rebel, and only then he abolished the senate.

It was dissolved after Leia was captured which gave Palpatine the ammunition he needed to cast doubt on the Imperial Senate's loyalty, he dissolved it not long after.

He gave them a whiff of his bad breath, which is enough to destroy half of Coruscant, honestly.

Palpatine planned on dissolved the senate after he finished the Death Star because if any planet opposed the Empire they could just destroy it.

You said it! He literally destroyed it in ROTS just as you say.

Thanks for your time everyone, I didn't expect all these answers! 👍

He dissolved it

In hot water

Then he drank it

Then he took a whizz & the senate became one with the Coruscant sewage system