The timing on this move is, to say the least, curious. One of the last three members of Barack Obama’s original Cabinet will announce his resignation today, according to multiple sources talking with NPR. Eric Holder will step down as soon as his replacement can be confirmed — and that may be quite a fight:

Eric Holder Jr., the nation’s first black U.S. attorney general, is preparing to announce his resignation Thursday after a tumultuous tenure marked by civil rights advances, national security threats, reforms to the criminal justice system and five and a half years of fights with Republicans in Congress.

Two sources familiar with the decision tell NPR that Holder, 63, intends to leave the Justice Department as soon as his successor is confirmed, a process that could run through 2014 and even into next year. A former U.S. government official says Holder has been increasingly “adamant” about his desire to leave soon for fear he otherwise could be locked in to stay for much of the rest of President Obama’s second term.

As Noah mentioned on Twitter, Holder has stuck around longer than most AGs in two-term presidencies, and only Arne Duncan and Tom Vilsack have served the entirety of Obama’s presidency on the Cabinet. Holder has been a lightning rod for controversy and scandal, especially in his fight to keep ATF and DoJ communications regarding Operation Fast and Furious from Congressional oversight. Holder still has an outstanding contempt citation and is still fighting in court to keep those documents under a highly-suspect claim of executive privilege.

That case will continue without him, of course, but it makes the next nominee to the post vulnerable to all sorts of questioning on how it will proceed in Holder’s absence. Nor is that the only problem facing Obama’s choice for Holder’s replacement during the Senate confirmation hearings. Republicans are likely to batter the appointee with questions about when the DoJ will get serious about the IRS probe, and Holder’s pressure on reporters such as James Rosen on leaks (and James Risen for that matter). All of these issues will become immediately important all over again, and will remind voters of just how much Holder has shielded the Obama administration from scrutiny and accountability.

Those are difficult subjects to bring up in a midterm cycle that already looks bad for Obama, so … why resign now, rather than after the election? The White House is apparently worried that a Republican takeover of the Senate will make confirmation of Holder’s replacement very difficult unless Obama appoints someone Republicans like. Resigning now allows Obama to appoint a replacement soon, and Senate Democrats to schedule the hearings during the lame-duck session (and don’t forget Harry Reid’s rule change on filibusters for presidential appointments, too, which expires at the end of this session). But naming a replacement for Holder carries significant political risks if it happens ahead of the midterms, too; if Obama picks someone too radical, Republicans will jump all over the choice in Senate races, and warn that the Democratic incumbents (or challengers, as the case may be) will be a rubber stamp for confirmation. It really puts the rubber-stamp issue front and center in the Senate races, which is exactly what Democrats who are trying to distance themselves from Obama didn’t need.

This is a resignation that would have been better timed for Obama in June, especially with the focus falling on foreign policy, and finished up before most voters started paying attention to the midterms.

Update: This is also curious timing in another sense:

Holder, widely rumored to have been planning his departure before the unrest in Ferguson thrust the Justice Department into the national spotlight, will announce his resignation Thursday afternoon, according to a Justice Department official.

The Ferguson unrest seemed to capture Holder’s imagination, but nothing much has happened since. Why wouldn’t he stick around to see it through? Maybe the federal investigation is proving to be a dead end, or just too much of a political headache. Democrats on the Senate Judiciary Committee will probably be discussing Ferguson during a confirmation hearing, which may end up backfiring on the nominee if nothing comes of it.

Update: By the way, Holder lost again in court on Fast & Furious:

“The government’s arguments for even more time are unconvincing,” Bates said in his ruling. “[S]eventy-five days—plus another twenty-one, based in part on Judiciary Watch’s consent—is enough time for the government to prepare the index that this Court has ordered, given that this matter has been pending for over two years. The Court will therefore extend the Department’s Vaughn index submission deadline to October 22, 2014—and no further.”

“The government argues that it must devote significant numbers of attorneys to this matter if it hopes to comply with the current Vaughn index deadline … But the Department has known about its Vaughn index obligations since July 18, 2014 … At best, it means the Department has been slow to react to this Court’s previous Order. At worst, it means the Department has ignored that Order until now,” he added.

I think Holder will lose the entire case, which is another reason to be gone when that happens.