Will the real attorney general please stand up?

As was widely expected following the publication of a New York Times story outlining the state's case, Maryland has challenged President Trump's appointment of acting Attorney General Matthew Whitaker in federal court, arguing that Deputy AG Rod Rosenstein should instead be elevated to replace Sessions.

In effect, the state is using an unusual legal maneuver to force federal judge Ellen L. Hollander of the Federal District Court for the District of Maryland - a 2010 Obama appointee - to decide who is the legitimate attorney general. Two months ago, the state's attorney general sued Jeff Sessions in his official capacity as AG, seeking a declaration from the court that ObamaCare is, in fact, constitutional, even without the tax penalty component, which was repealed by Congress. The lawsuit was an attempt to stop a federal judge in Texas from throwing out the law in its entirety.

Now, the state is asking Hollander to clarify who is the real attorney general so this person can stand in for Sessions as the object of Maryland's ObamaCare lawsuit. Because the government's enforcement of ObamaCare is set to change on Jan. 1 to reflect the removal of the tax penalty, the state is demanding that Hollander make this crucial ruling immediately to stop Whitaker from making illegitimate policy decisions as head of the DOJ.

This will force Hollander to rule on whether Trump's invocation of the Federal Vacancies Reform Act, a 1998 law which stipulates that a president may temporarily fill a vacant position that normally requires Senate confirmation with any senior official who has been in the department for at least 90 days. By appointing Whitaker, Trump overruled the natural line of succession at the DOJ, which would have installed Rosenstein as the acting AG until another AG candidate could win approval from the Senate.

Democrats have slammed Trump's decision to invoke the Vacancies Reform Act, which he previously used to successfully replace outgoing CFPB Director (and failed gubernatorial candidate) Richard Cordray with OMB head Mick Mulvaney. Chuck Schumer, the leader of Senate Democrats, has demanded that Trump explain why he installed Whitaker instead of handing the reins to Rosenstein.

Meanwhile, Dianne Feinstein is calling for the Senate Judiciary Committee to demand Sessions and Whitaker testify about the circumstances surrounding Sessions' ouster and Whitaker's ascension, according to the Hill.

The hearing is needed, Feinstein said, to "ensure that he will take no action to restrict or otherwise interfere with the Special Counsel’s work."

Whitaker has so far ignored Democrats' demands that he recuse himself from the Mueller probe, though he has said he wouldn't act to terminate it. GOP Sen. Majority Leader Mitch McConnell has said he would block any bills aimed at preserving the Mueller probe.

So, as the next round of Mueller indictments reportedly looms, all eyes will be on Maryland to see if a federal judge could upend the DOJ depth chart, unleashing line-of-succession chaos that could persist until Trump secures a replacement.