SPRINGFIELD, Ill. -- Gov. Rod Blagojevich's arrest Tuesday morning raised immediate questions about who is running state government while he is in custody.

Along with Blagojevich, the Federal Bureau of Investigation arrested his chief of staff, John Harris, who oversees much of the day-to-day management of state government.

At 9 a.m. in the governor's press office on the second floor of the State Capitol, Blagojevich spokesman Brian Williamsen would not confirm the governor's arrest.

Williamsen said employees in the office were continuing to work.

''We're here to do our jobs,'' Williamsen said.

But there are numerous pressing issues facing the governor and state government that were thrown into limbo while the legal process sorts itself out.

Among them were:

- The appointment of a replacement for U.S. Sen. Barack Obama;

- Plans to close Pontiac Correctional Center;

- And, the financial mess facing state government.

University of Illinois-Springfield political scientist Kent Redfield said it's still Blagojevich's call to appoint a successor to serve out the remaining two years of Obama's Senate term.

Because of that, Redfield said, federal prosecutors may try to prod Blagojevich into resigning soon. Earlier this year, New York governor Eliot Spitzer resigned after charges against him were announced.

''The governor is governor until he's removed from office or forced from his office,'' Redfield said.

If Blagojevich resigns or is removed from office, he would be replaced by Lt. Gov. Pat Quinn, a former state treasurer who has served under Blagojevich since 2003.

Quinn was expected to issue a statement later in the day Tuesday.

Lawmakers, meanwhile, aren't due to return to action until Jan. 12. It was not clear whether the governor's arrest would prompt legislative leaders to bring the General Assembly back to town before then.

Even before the arrest, however, some lawmakers were talking about impeaching Blagojevich because of the on-going federal investigation.

The governor's arrest Tuesday follows a trend in Illinois dating back 45 years, in which three former Illinois governors had been convicted of crimes.

Otto Kerner, who served from 1961 to 1969, was convicted of bribery.

Dan Walker, who served from 1973 to 1977, was convicted on charges related to financial dealings after his term ended.

Blagojevich's predecessor, George Ryan, is currently serving a 6 ˝ year sentence in a federal prison in Indiana after being convicted for corruption.

(Kurt Erickson can be reached at kurt.erickson@lee.net or 217-789-0865)