The man who will serve at least temporarily as the nation's top law enforcement official is Matthew G. Whitaker.
But the key collusion and obstruction questions that underpin the investigation remain unanswered, and a grand jury in Washington continues to hear evidence about Trump confidant Roger Stone.
The timing for when a final report would be submitted by the special counsel's office is still unclear, and sources say there is also no clear timeline for when Mueller will wrap his investigation.
Speeches from officials and protesters were punctuated with honks of support, chants of "Hey hey, ho ho, Donald Trump has got to go", and a cry of "Witch hunt!" from a passing auto.
"He is just a frightful human being, and the fact that he did one thing that we might consider to be somewhat ethical by recusing himself from the Mueller investigation, now all of a sudden he's everybody's hero".
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"We're here because Trump replaced Sessions and installed someone who will do his bidding, who has voiced his hostility to the Bob Mueller investigation", said Mary Melancon, 75, of Tampa. "Worth a read", he tweeted. Marvin Gaye's "What's Going On" played on loudspeakers as protesters crowded into the plaza, waving signs with phrases like "Back off from Mueller".
That left Rosenstein overseeing the investigation, and he named Mueller as special counsel.
She went on to argue that, "given his record of threats to undermine and weaken the Russian Federation investigation", Mr Whitaker should follow in Mr Sessions' footsteps and recuse himself. Whitaker very vocally believes otherwise. During that campaign, one of his chief pledges at a GOP forum was that he would ask candidates for a federal judgeships whether they are "people of faith" who had "a biblical view of justice".
The Supreme Court is an "inferior branch" that should not have any authority over Congress.
Democratic Senator Richard Blumenthal of CT also criticized Whitaker's appointment.
St. Petersburg Mayor Rick Kriseman told the crowd that firing Sessions already amounted to the "biggest constitutional crisis we have seen since Watergate".
Interestingly enough, however, in the same breath, he also said the Supreme Court should have repealed the New Deal and the Affordable Care Act - neither of which would be possible without Marbury.
"If the president seeks to interfere in the impartial administration of justice, the Congress must stop him".
Kovalik said he was anxious about the future enforcement of the nation's civil rights laws under Whitaker, but he welcomed the end of the Russiagate investigation, which has served only to heighten tensions with Russian Federation and found nothing in terms of its actual scope in the 18 months it's been looking.
"Every president deserves an attorney general they have confidence in and they can work with", he said.
Her words were echoed by Democratic party Senate leader Chuck Schumer, who added: "Clearly, the president has something to hide."