A week after e-mails in the U.S. attorneys case became a main focus of the probe by congressional Democrats, several staffers said that they stopped using the White House system except for professional correspondence.

"We just got a bit lazy," said one aide. "We knew e-mails could be subpoenaed. We saw that with the Clintons but I don't think anybody saw that we were doing anything wrong." Bedard reported that some aides said they bought private e-mail accounts and are relying on text-messaging on personal cellular phones.