Ferman still has ardent supporters. But in separate interviews, four Republicans and Democrats active in county political and legal circles said her political vulnerability had become a topic of quiet discussion, one that surfaced even at the county GOP membership meeting this month at the Westover Country Club in West Norriton.
"Everybody was talking about it, saying that they think she's damaged - maybe we ought to look for someone else to run," said one attendee. (Like others, she agreed to speak only if her name was not used, for fear of alienating Ferman or her supporters.)
Montgomery County Republican Committee Chairman Mike Vereb said he was unaware of the talk.
"No one in this party has been approaching me saying she has to go," said Vereb, a state representative. He said Ferman had accomplished what the public wants a district attorney to do - she "put the bad guys in jail."
Ferman has not decided whether she will seek a third term, she said in an interview last week. As to missteps by her office, she said she had been involved with tens of thousands of cases in 22 years as a prosecutor.
'The right thing'
"I have no delusion that everything will go perfectly," she said. "Recent events demonstrate I'm a dedicated public servant, committed to justice and to upholding my responsibility to do the right thing."
The 49-year-old Abington Township resident worked as a prosecutor for 15 years in Montgomery County, eventually leading the sex-crimes unit and becoming the office's second-in-command to District Attorney Bruce L. Castor Jr., who now is a county commissioner.
She was elected district attorney in 2007 with 56 percent of the vote against Democratic challenger Peter C. Amuso and reelected without opposition.
Marcel L. Groen, chairman of the Montgomery County Democratic Committee, said the party opted not to run a candidate against her in 2011 so it could focus on electing Josh Shapiro and Leslie S. Richards as county commissioners. In next year's district attorney race, Groen said, "we probably will put out a candidate."
In interviews, both Republicans and Democrats said the two recent cases had stirred doubts about whether Ferman keeps a close enough watch on her office or is influenced by political connections and timing.
The case against Kerns - the head of Ferman's own political party - was thorny from the start. Her office used a grand jury to investigate then charge him in November with raping a woman who worked with his law firm after drugging her with the sleep aid Ambien.
Kerns denied any wrongdoing, and the case was headed to trial.
But in March, Ferman's office admitted that its staffers had misread a crucial lab report - and that there was no proof the woman had been drugged. Ferman did not back down from the rape allegations but said her office had become too conflicted to prosecute the case, so she dropped all charges and referred the case to the Pennsylvania Attorney General's Office.
State prosecutors have since filed new charges against Kerns.
In the other case, a civil lawsuit settlement finalized last month forced the county to pay $1.6 million to Walter Logan, a Radnor Township contractor who claimed he was wrongly charged with stealing money from a Jenkintown church where two high-ranking county officials were members.
Under the settlement, Ferman, who once called a news conference to announce the charges against Logan, not only dropped the case but took the unusual step of apologizing to him, although she maintained that politics played no part in the decision to bring the case.
She has since fired the lead detective in the case.
She has also launched a comprehensive review, which is still going on, after the Kerns case to improve processes and prevent similar mistakes from occurring. Ferman will not talk about disciplining anyone in her office for the misread lab report.
But she cannot avoid some blowback from both cases, experts said.
"She's going to be more open to criticism now because of the handling of these cases," said John J. Kennedy, an associate professor of political science at West Chester University who lives in Montgomery County.
Ruth Damsker, a Democrat and former county commissioner running for state Senate, said she believed Ferman "may be more vulnerable than she ever has been," and cited the Kerns case as a reason. "It was a little surprising, that it had been so sloppily done without oversight," said Damsker, who said Democrats should always run challengers against incumbents.
One politically active Republican said the cases highlight an image Ferman has among some in the legal and judicial communities "that she is far too hands-off, far too interested in the collateral things of being district attorney."
Ferman disagreed, and said a children's book she wrote on Internet safety and office initiatives she began can help prevent crime.
She still gets praise, locally and statewide.
"Anything I've ever heard about Risa Ferman has been exceptionally positive," said Charlie Gerow, a Republican media strategist based in Harrisburg. "In my judgment, these are flesh wounds and nothing more."