By Alan K. Ota, CQ Staff

Former Speaker J. Dennis Hastert has now officially resigned from the House.

Hastert made his resignation effective at 11:59 p.m. Monday to clear the way for Illinois Gov. Rod R. Blagojevich to schedule a special primary election Feb. 5 to fill his vacant seat.

In a letter to Blagojevich, Hastert, R-Ill., said he was resigning immediately to expedite the process for choosing his successor. “I have chosen this date because I have been advised that it allows you sufficient time to call a special primary to select candidates to run to fill my unexpired term on February 5, 2008, an already established primary day. This will minimum inconvenience to the voters and expense to the counties,” Hastert wrote.

In a written statement, Hastert thanked his constituents for allowing him to serve 21 years in Congress. “I am grateful to them and proud of all that we have been able to accomplish together. But the time has now come to spend more time with my family which sacrificed for so long to enable me to serve,” he said.

Hastert also wrote Speaker Nancy Pelosi , D-Calif., to inform her of his resignation.

“Let me also thank you, Madam Speaker, for the many courtesies you have afforded me as a former Speaker during the past year and I wish you and all my colleagues God’s blessing as you continue in your service,” Hastert told Pelosi.

Hastert, 65, who served as Speaker longer than any Republican in U.S. history, had previously announced his intention to resign but had not set a date.

He delivered a farewell speech from the well of the House Nov. 15.

Hastert’s sudden departure sets up a scramble to fill his seat as ranking Republican on the Energy and Commerce Subcommittee on Energy and Air Quality. Rep. Fred Upton , R-Mich., just below Hastert in seniority on the full committee, has said in recent weeks that he will take a look at the job, but has not decided whether he would swap out of his current job as ranking Republican on the Telecommunications and Internet Subcommittee. Rep. Cliff Stearns , R-Fla., just below Upton in seniority, has said he also might want to succeed Hastert on the subcommittee, but would have to give up his current post as ranking Republican on the Commerce, Trade and Consumer Protection Subcommittee. Edward Whitfield , R-Ky., has said he would have an interest in becoming ranking member on the Energy and Air Quality Subcommittee.