How to oust Blagojevich from office if he won't resign and the legislation won't impeach him.

There's this:

"I have the opportunity to go to our Illinois Supreme Court and ask them to declare our governor is unable to serve and put in our lieutenant governor as acting governor," [Illinois Attorney General Lisa] Madigan, a longtime Blagojevich foe who is considering a run for governor in 2010, told CNN.

What legal procedure is this exactly? I can see that the Illinois Constitution provides, in Article V, Section 6:

(b) If the Governor is unable to serve because of death, conviction on impeachment, failure to qualify, resignation or other disability, the office of Governor shall be filled by the officer next in line of succession for the remainder of the term or until the disability is removed.

(c) Whenever the Governor determines that he may be seriously impeded in the exercise of his powers, he shall so notify the Secretary of State and the officer next in line of succession. The latter shall thereafter become Acting Governor with the duties and powers of Governor. When the Governor is prepared to resume office, he shall do so by notifying the Secretary of State and the Acting Governor.

(d) The General Assembly by law shall specify by whom and by what procedures the ability of the Governor to serve or to resume office may be questioned and determined. The Supreme Court shall have original and exclusive jurisdiction to review such a law and any such determination and, in the absence of such a law, shall make the determination under such rules as it may adopt.

Does this mean the AG can oust the Governor over the kinds of matters that would also be grounds for impeachment? Is his arrest an "other disability"? That seems to be Madigan's theory according the Chicago Tribune:

The Illinois Constitution is vague enough that she could argue the governor's corruption charges are enough to be considered a "disability" — a condition typically associated with physical or mental issues.

... Another portion of the Constitution opens the door to considering whether Blagojevich is "seriously impeded in the exercise of his powers." The argument again is that the taint of the allegations—that the governor sought to trade official state actions for personal gain—means he can't govern.

The "seriously impeded" language is plainly left to the Governor's own judgment about himself. So I think Madigan is limited to characterizing the ongoing prosecution as a "disability" -- and convincing the court that this is appropriate.

The Tribune continues: "Would Madigan go to court so her father, House Speaker Michael Madigan, can avoid a messy impeachment?" That makes the idea of end-running impeachment look quite a bit worse.

UPDATE: Madigan files the case.

ANOTHER UPDATE: On the oral argument to the state court.