The five are accused of extorting hundred of thousands of dollars in bribes from developers trying to win bids on large city projects.
Miller's name has come up repeatedly in the trial because she received substantial campaign contributions from affordable housing developer Brian Potashnik.
Potashnik said Hill and the co-defendants forced him to pay them in exchange for their votes on his projects. He was charged in the case, but pleaded guilty on the eve of the trial in exchange for his testimony against the others.
Defense lawyers argue Potashnik's financial support for Miller was a greater influence and that Miller repeatedly voted in favor of Potashnik's projects. They now question why the FBI did not target Miller.
Defense attorney Victor Vital said Miller also appointed Potashnik to a city task force, which boosted his stature, and wrote a glowing letter of recommendation for him.
"She did not do that for any other developer," said Vital.
Federal authorities have said they do not believe Miller was doing anything improper. Postashnik's payments to Miller were documented campaign contributions and the government alleges Hill received hidden bribes.
Miller testified that she was a strong supporter of stronger ethics rules at City Hall, including an ethics commission that would review complaints.
Miller said Hill opposed many of the changes, including the ethics commission.
The prosecutor played a tape of a May 2000 city meeting at which Hill called the ethics plan "much to do about nothing." Hill complained that the new rules were unreasonable restrictions on the council, which had just become majority minority.
"He had legitimate concerns, not about the ethics, but how they were going to be applied," said Hill's attorney Ray Jackson.
Miller also testified about an August 2003 city council meeting where she learned that Councilman James Fantroy, now deceased, had a deal with a developer.
Fantroy's security company would receive a contract with developer Bill Fisher if Fisher's apartment project in Fantroy's district was approved. Fisher is a government informant in the case.
Miller raised objections about the deal at the time.
"Mr. Hill said that he didn't understand what my concern was," Miller testified.
At the lunch break, defense attorneys said issues concerning Fantroy are irrelevant in this trial.
"We have the government trying a case against a dead man that they chose not to indict in this case," Vital said.
Fantroy recused himself from voting on the project in 2003. He was never charged with a crime over that issue, but was convicted of embezzling money from Paul Quinn College. He died after a long battle with cancer in October 2008.
Miller will return to the witness stand Friday morning for more defense questions. The trial could last several more weeks.