WASHINGTON, D.C. - Could the acting United States Attorney General be summoned before the Senate Judiciary Committee?

That’s the goal of some Senate Democrats, including Hawaii Senator Mazie Hirono, who says Matthew Whitaker’s appointment by President Trump is “constitutionally invalid” and a conflict of interest in the Russia probe.

Whitaker was appointed after Attorney General Jeff Session was forced to resign last week, one day after Democrats won the U.S. House and gained control into oversight and investigation committees.

This week, the committee’s ranking member Dianne Feinstein (D-Calif.) requested Judiciary Chairman Chuck Grassley (R-Iowa) to hold committee hearings with both Whitaker and Sessions.

Democrats are calling on Whitaker to recuse himself from Special Counsel Robert Mueller’s investigation into potential Russian collusion with the Trump campaign in the 2016 election. That recusal is the reason many believe Sessions was ousted last week, meaning it’s unlikely Whitaker will do that.

Other Democrats argue that Whitaker’s appointment violates the rules of succession, and therefore the Constitution. Right now, Deputy Attorney General Rod Rosenstein is overseeing the special counsel’s investigation into any Trump/Russia collusion.

On Hirono’s claim that Whitaker’s appointment is “constitutionally invalid,” Whitaker as attorney general would become a “principle officer,” someone who reports directly to the president. People who hold those positions need to be confirmed by the Senate, Hirono said.

Judiciary Committee Democrats also want both men – notably Whitaker – to appear for the hearing as soon as possible.

“I think (Whitaker) should (appear before the Committee) because he should be confirmed,” Hirono said in an interview with KITV 4 Island News this week. “Now there are those who say that he doesn’t need to be confirmed citing, by the way, precedent that goes back to before the 1900s. Give me a break.”

That any hearing likely wouldn’t happen until the next Congress officially convenes in January, Senate aides said.