Hillary Clinton's use of a personal email account for conducting State Department business followed both federal rules in place at the time and the practice of some of her predecessors, her lawyer says.
The explanation, from Washington, D.C. lawyer David Kendall, comes in a letter sent late Friday to the State Department's undersecretary for management, obtained by NBC News.
"Secretary Clinton's use of personal e-mail was consistent with the practice of other Secretaries of State and was permissible under State Department policy in place during her tenure," Kendall writes.
Though styled as a letter to the State Department, it amounts to a response to a comment Thursday from a federal judge during a hearing over a lawsuit to obtain government records.
“We wouldn’t be here today if this employee had followed government policy,” said Emmet Sullivan, a federal district court judge in Washington, referring to Clinton.
The court hearing involved a side issue in the e-mail controversy — a Freedom of Information Act request for records detailing an arrangement that allowed top Clinton aide Huma Abedin to do outside consulting while working at the State Department.
In his latter, Kendall quotes from a memoir by former Secretary of State Colin Powell who wrote that he used his personal email account for messages to "principal assistants, to individual ambassadors, and increasingly to [his] foreign-minister colleagues."
Clinton's use of her personal account was also permitted by federal regulations, Kendall says, including rules issued by the National Archives to implement a federal law on record preservation.
In 2009, Kendall says, the rule explained the practice to be followed when federal agencies "allow employees to send and receive electronic mail messages using a system not operated by the agency."
In that event, the employee must ensure that a record of the email is obtained in a government system. "Secretary Clinton followed that regulation through her practice of communicating with other Department officials on their state.gov e-mail accounts," Kendall's letter says.
By forwarding and copying messages to department employees at their government addresses, her emails were preserved in the State Department system, he said.
Kendall also said Clinton followed government regulations in deciding which emails in her personal accounts were private and which involved official business.
Both federal regulations and the State Department's Foreign Affairs Manual contemplate that kind of review by employees. The manual, Kendall notes, offers guidance "to direct the preservation of those messages that contain information necessary to ensure that departmental policies, programs, and activities are adequately documented."
Clinton provided the State Department printed copies of 30,490 emails from her personal account last December. Roughly 90 percent of them were sent to or received by a government employee with a state.gov address, Kendall said.
Of the rest, Kendall says, "we anticipate that many" will prove to have been of a personal nature that did not need to be preserved.
In March 2015, the Government Accounting Office found that the State Department’s archiving system was seriously flawed and that only a small percentage of e-mails were actually saved during the period in question.
But Clinton campaign officials have said that if not for her private email system, many of the messages she sent during that period might not have been saved if she had used a state.gov account.
"That's one of the ironies here," a campaign official said Saturday. "If not for the records now available from her personal accounts, many of the e-mails she sent during that period would not have been archived."