WASHINGTON  When Representative Jan Schakowsky, an Illinois Democrat, began exploring whether she might fill Barack Obama’s seat in the United States Senate, she called Rahm Emanuel. They served in the House together and, more important, he had just become chief of staff to the newly elected president.

But Mr. Emanuel was uncharacteristically circumspect. If Mr. Obama had a favorite, Mr. Emanuel was not saying. And to Ms. Schakowsky, he seemed wary about Gov. Rod R. Blagojevich, who would be making the appointment. “Rahm always has good intelligence,” she recalled. “In this case, he really didn’t. It was not clear to him what the governor was going to do, or at least he didn’t share it with me.”

For the Obama team in the days after his election to the presidency, the question of who would succeed him in the Senate was a sensitive one. With a new administration to build and a financial crisis worsening by the day, Mr. Obama and his advisers had bigger issues on their plate. Moreover, they wanted to keep their distance from Mr. Blagojevich, who was already known to be under federal investigation into possible corruption. But many still assumed that Mr. Obama’s voice would be critical if he chose to weigh in.

Exactly what role he or his team played will be a focus of intense scrutiny in the weeks to come after the arrest of Mr. Blagojevich on accusations that he was plotting to trade or sell the Senate appointment. In that sense, the furor could be the first test of the Obama team’s ability to manage a growing scandal in an era when intense media scrutiny and partisan attack machinery can escalate any flap into a serious political problem.