My opinion would be that after the senate hearing anyone paying attention to Michael's doings (general public, or government) would already "know" what he is really about. The idea that he had to go out of his way to protect his "legitimacy", even if that is what he truly thought, was ridiculous because everyone would know that he was not "legit". You would have to be blind not to know what he was about.

However - without any proper evidence - none of it could actually be proven beyond any type of doubt. So - the fact (or very high likelihood) that Rocco was never going to make it out alive - means that Michael had very little/almost zero chance of anything coming of it. Anyone paying attention probably would assume Michael ordered the hit anyway (whether Rocco or someone else executed it).

Who knows that is just my take.