In every season of Cabinet confirmation hearings for an incoming president, there are two intertwined dynamics at play: the performance of the nominees who will carry out the new administration's agenda and the performance of the senators who hope to be assembling their own administration one day.

So when Sen. Cory Booker of New Jersey made the exceptional move Wednesday to break with Senate tradition and testify against a colleague's nomination, it was widely viewed as an opening move reflecting his ambitions to run for president.

"I believe, like perhaps all of my colleagues in the Senate, that in the choice between standing with Senate norms or standing up for what my conscience tells me is best for our country, I will always choose conscience and country," explained the 47-year-old Booker, who is still in his first term.

He was referencing the choice of Sen. Jeff Sessions of Alabama, whom Trump has nominated to become the nation's 84th attorney general. Sessions has been pelted by accusations he harbored racist beliefs in the past and therefore wouldn't protect civil rights in the future.

Even though a year ago he had partnered with Sessions to honor civil rights marchers in Selma – the hallowed city in the nominee's home state – Booker surmised that elevating him to be the highest ranking law enforcement officer in the country was a bridge he could not cross.

"I want an attorney general who is committed to supporting law enforcement and securing law and order – but that is not enough," he said.

Seated before the Senate Judiciary Committee, Booker made a funereal impression. Wearing a black suit and a solid black tie over a crisp white shirt, he was flanked by civil rights icon Rep. John Lewis of Georgia. Behind him sat members of the Congressional Black Caucus.

This was a clear decision to not only side with the band of civil rights groups leading the opposition to Sessions, but to trademark himself as a leader of it.

"Sen. Sessions has not demonstrated a commitment to a central requisite of the job: to aggressively pursue the congressional mandate of civil rights, equal rights and justice for all of our citizens," Booker said in his seven-minute testimony.

To Capitol Hill observers, the intention of Booker's performance was painstakingly transparent.

"This process should be about facts, not about political aspirations," said William Smith, an African-American staffer for Sessions who testified after Booker.

But opposing Sessions amounted to Booker's first campaign overture to the hearts of progressives, who see Sessions' ascendance as a frightening turn back to another era.

A "no" vote in itself wouldn't offer an opportunity to stand out; but taking the additional step of flouting Senate tradition sure would. It provided an example of risk-taking in the form of smashing established protocol, an attribute that gained historic traction during the 2016 race.

There are other senators who have already made their mark In this week's series of hearings.

Sen. Marco Rubio of Florida, whose optimistic sheen was dulled by Donald Trump in 2016, won the round of Rex Tillerson headlines through an unrepentantly aggressive inquisition of the president-elect's nominee for secretary state.

And Sen. Tom Cotton of Arkansas , who was taking steps towards a 2020 bid of his own before Trump's surprise victory, earned a slice of the Booker story by panning the New Jerseyan's move as "disgraceful."

Whether one views it as valiantly principled or patently political, grandstanding in Cabinet hearings that earn wall-to-wall cable coverage has become the norm.

After Booker testified, CNN asked him if he was open to a 2020 run. He replied that he was "open to doing everything I can right now as the Trump administration's coming in."

For Booker, that includes taking his case outside of New Jersey.