This was hardly the first time Harris has called for an independent investigation of Trump's ties with Russia. But the statements continue a pattern from these two Democrats, with Feinstein providing measured pragmatism as Harris plays to the party's base.

"What we see is somebody who's not going to run for higher office again and somebody who wants to run for president," said Loyola Law School professor Jessica Levinson.

On Feinstein, Levinson said: "We see someone who’s winding down her career and may have to wind down because she’s been so unemotional about things people want to see her fired up about."

Harris, on the other hand, was doing "the politically expedient thing," Levinson said. "That’s very much her. She’s been running for office since she learned how to walk."

At a time when Democrats see blood in the water over the recent House passage of the American Health Care Act, Harris is upping the ante. During a recent interview for the Pod Save America podcast, California's junior senator called on the live audience to help defeat the seven Republican members of Congress from California deemed most vulnerable.

"If the Republicans want people to lose their health care, then the Republicans need to lose their jobs," Harris said to a cheering live audience. "Go to Darrell Issa's district and knock on doors."

At her recent town hall meetings, Feinstein has been urged to adopt a more strident, anti-Trump tone. But it's not really her style.

"She has been political royalty for a very long time," law professor Levinson said. "She seems to believe that if she’s going to have another term in the U.S. Senate, it's going be on her terms."

Update 7:53 a.m., Wednesday:

Early this morning, Sen. Feinstein's office released a second statement on the Comey firing, this one much more pointed.

“If Director Comey was fired to stifle the FBI’s Russia investigation—and the timing of this action makes that a real possibility—that simply can’t be allowed to happen," the statement read.

“Toward that end, I plan to work closely with Senator Blumenthal on the appointment of an independent prosecutor. I will also support Deputy AG Rosenstein in the appointment of a special counsel who should be far removed from the politics of this place."