Here's how Trump's new attorney general could be legally bound to protect Robert Mueller: MSNBC

A precedent set during the Watergate era may lead to more legal protections for special counsel Robert Mueller, MSNBC's Ari Melber reported Friday night.

In a special report, Melber noted that the Senate "not only decides whether to approve the attorney general, but it can require that this attorney general, under oath, will back up Bob Mueller."

"We know that," Melber said, "because it's happened before."

President Richard Nixon, like Donald Trump, was under investigation by his own Justice Department when he appointed Elliott Richardson to become his attorney general.

As with today's political climate, the "crucial" question then was whether the new AG would allow Archibald Cox, the person tasked with investigating Watergate, to be truly independent and to finish their probe unimpeded.

"Back in '73, the Senate didn't simply vet Richardson," Melber said. "It used those hearings to extract a binding arrangement under oath to protect the special prosecutor's Watergate probe, demanding that the Watergate prosecutor would get final authority."

Richardson initially pushed back, the host noted, but "the Senate stopped him right then and they said they wouldn't even hold a hearing until he committed to more independence."

"The senators didn't know that trail would lead to a White House with a secret taping system," Melber said, "but they knew enough about the Constitution to use the Senate as a check against Nixon's attempt to kneecap the DOJ. Richardson was confirmed on the assurance that he would not intervene in the probe on Nixon's behalf."

Amid ample comparisons between Trump and Nixon, the host pointed out that the current president is "much worse" than his predecessor.

"Let's be clear: Donald Trump is no Richard Nixon -- he's way worse," Melber said. "More openly hostile to rule of law, more disrespectful to the FBI agents that risk their lives."

"Nobody knows where Mueller is headed exactly," he added, "but next week's hearing could decide where he's allowed to go and if he's allowed to hold Mueller back or keep the report secret."

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