By John McDevitt

PHILADELPHIA (CBS) — Convicted abortion doctor Kermit Gosnell, currently serving three consecutive life sentences for the murder of infants born alive, was back in court today, refusing to sign a goverment plea agreement on federal drug charges.

Dressed in a green prison jumpsuit, Gosnell pleaded not guilty in the federal case, rejecting  the plea agreement.  Now, the case will go to trial.

Gosnell is charged with illegally prescribing  painkillers and sedatives outside the usual course of professional practice, along with related charges.

“I think the position that he is taking at this point in time is that was done, obviously, on occasions,” acknowledges defense attorney Jack McMahon.  “How much of  it was done, and how much of it is responsible to him is somewhat of the sticking point here,  but I don’t believe he’s saying he is someone without fault.  It’s just a question of what and how much fault.”

The trial is scheduled for September 9th.

Gosnell had been expected to plead guilty today to charges he illegally distributed painkillers, which would have tacked on a 20-year sentence to the life terms he’s currently serving.

Prosecutors say the Gosnell ran a “pill mill” by day and a rogue “abortion mill” by night at a filthy clinic in West Philadelphia.

Gosnell was convicted in May in the deaths of three babies born alive at his clinic (see related stories).