Maybe firing Comey was legal. Some lawyers say the president can remove the FBI Director at will. Others argue these circumstances constitute obstruction of justice.
There’s no question it was legal; Comey works for Trump, after all. And everyone in the Administrative Branch serves at the pleasure of the President.
Also, there’s no way a firing can be obstruction of justice. Obstruction of justice is something tangible, like shredding documents or erasing tapes (Nixon) or lying under oath (Clinton). Firing Comey just means somebody else picks up the investigation. Thus, no obstruction. Unitary executive, and all that.
So, in that regard, it sounds like you want Congress to stand up and support a full investigation of something that was completely legal.
This is a time for statesmen. Republican Senators, start leading the effort for a rapid, thorough investigation. Get out in front of the issue. Make sure it’s done right.
So, basically, you want to put pressure on the Republican senators to do what they already said they want to do.