"It was like, 'Here’s a manual, go fly the space shuttle'"

After initially being more evenly split on that question, 11 jurors repeatedly cast votes in favor of convicting on the charges connected to it — charges that included bribery, conspiracy, extortion conspiracy and racketeering. Many in the group felt that this was the prosecution’s strongest case, and the set of counts that the jury was most likely to agree on.

But one juror, a woman whom other jurors declined to identify, saying they wanted to respect her privacy, never budged in her opposition to convicting on the counts. She was unmoved by recorded calls in which Mr. Blagojevich and his aides spoke of possible jobs, donations, even a White House cabinet appointment he might get after making his Senate choice.

Mr. Wlodek described her stance as “very noble,” adding: “She did not see it as a violation of any laws. It was politics. It was more of conversations of what-ifs.”

Another juror, Erik Sarnello, a student from the suburbs, said: “She just didn’t see it, didn’t think they had proven it. She wanted clear-cut evidence.”