CNN  — 

A bill that would protect special counsels such as Robert Mueller was once again not allowed a vote on the Senate floor Wednesday.

Republican Sen. Jeff Flake of Arizona and Democratic Sens. Chris Coons of Delaware and Cory Booker of New Jersey attempted to force the vote by unanimous consent, but that meant it could be blocked by just one senator, as Republican Sen. Mike Lee of Utah did Wednesday.

Senate Majority Leader Mitch McConnell has argued, as recently as Tuesday, that the bill is not necessary since he believes there is no indication President Donald Trump is moving to fire Mueller.

Flake disputed McConnell’s argument in his floor speech ahead of his vote being blocked.

“Why shouldn’t we be up in arms about this?” Flake said reading a few of Trump’s recent tweets about Mueller. “Should we here in the Senate be okay with that? I argue no, we should not be.”

“With the President tweeting on a regular basis – a daily basis – that the special counsel is conflicted, that he’s leading so called ’12 angry Democrats’ and demeaning and ridiculing him every way,” Flake, who is retiring at the end of his term in January, continued. “To be so sanguine about the chances of him being fired is folly for us, I believe.”

In his remarks, Booker pointed to Trump’s recent tweets about Mueller and his appointment of acting attorney general Matt Whitaker, a vocal critic of Mueller’s investigation. In his position as acting attorney general, Whitaker now oversees the Mueller investigation.

“We know the special counsel office is in danger,” Booker said.

In his opposition to the bill, Lee cited the late Justice Antonin Scalia’s minority opinion in Morrison v. Olson, the Supreme Court case that upheld the process of appointing an independent counsel under a bill passed forty years ago. That law’s authority has expired.

“As Justice Scalia explains, we cannot convert an office like this one, an office like the previously existing office of independent counsel, without creating a de facto fourth branch of government fundamentally undermining the principles of the separation of powers that is so core to our liberty,” Lee said.

Coons said that he is confident if the bill were brought to a floor vote it would get the 60 votes needed to pass. He says he will continue to push for it.

Aides to the senators knew the bill would be blocked and hope this effort is about creating momentum and keeping pressure on leadership. Flake and Coons had previously tried to push such a bill shortly after Whitaker’s appointment earlier this month, following the firing of then-Attorney General Jeff Sessions. That bill was also blocked.

On Tuesday, Senate sources told CNN that Republicans may let the bill come up for a vote, in an effort to win over Flake who has vowed to vote against pending judicial nominations until the measure is considered by the chamber. Flake can not only slow nominations down on the floor but wield more influence as a member of the Senate Judiciary Committee.

CNN’s Alex Rogers contributed to this report.