The judge, Col. James Pohl, said during a pretrial hearing that he believed England did not fully understand the consequences when she waived her rights against self-incrimination before speaking to the investigators in January 2004.
Pohl did not elaborate on his ruling, which came after testimony from expert witnesses who said England tended to try to please people in authority and that she had trouble understanding complex language.
However, the judge did agree to a prosecution request that they be allowed to present evidence to get one of the two statements readmitted.
The statements were important components of the prosecution's case against England, who is charged with committing abuses at Abu Ghraib in 2003.
England, 22, a reservist from West Virginia who appeared in some of the most notorious photographs from the scandal, is charged with conspiracy, maltreating detainees and committing an indecent act. The charges carry a maximum sentence of 11 years in prison.
Also Thursday, Pohl refused to step aside for the trial, saying he was not to blame for England's botched attempt in May to plead guilty to illegal acts.
Defense lawyers accused Pohl of undermining England's guilty plea by asking inappropriate questions of Pvt. Charles Graner, the reputed abuse ringleader who was called by the defense as a sentencing witness.
Pohl accepted England's guilty plea in May to the same charges she now faces, after questioning her to make sure she believed she was doing wrong at the time.
But the judge abruptly halted the sentencing after Graner's testimony, and after a long recess he declared the mistrial, which ended England's plea deal and put the case back on track for trial, now scheduled for early August.
England is the only soldier charged with abusing prisoners at Abu Ghraib whose case has not been resolved.
Graner and Spc. Sabrina Harman opted for trial on Abu Ghraib charges. Graner is serving a 10-year sentence for his role in the abuse. Harman was convicted of abuse in May and sentenced to about four months in prison. Six other soldiers have made plea deals that included sentences of up to eight years.