CHICAGO —  Hours after his overwhelming primary victory, Barack Obama (search) got a phone call that in many ways signaled his arrival as the new Democratic star in a Senate race with national implications. The man on the phone Wednesday morning was Democratic presidential candidate John Kerry, who called to congratulate the Ivy League-educated state senator and former civil rights lawyer for his victory.

Now the Republican candidate, Jack Ryan (search), faces a daunting task in trying to end Obama's political honeymoon while uniting a deeply fractured Illinois GOP and deflecting questions about his personal life.

Although 34 seats are up for grabs in November, Democratic leaders have targeted Illinois as a key battleground in their effort to regain control of the Senate. Obama is seeking to become only the third black U.S. senator since Reconstruction.

Illinois is widely seen as leaning Democratic, and has voted Democratic in the last three presidential elections. And many experts doubt President George W. Bush will invest much time or energy in pumping up Illinois Republicans.

Ryan, a millionaire investment banker who later became a high school teacher, again refused Wednesday to release all the documents from his 1995 divorce from "Star Trek: Voyager" and "Boston Public" actress Jeri Ryan (search). Jack Ryan says he has released everything except for documents pertaining to his 9-year-old son.