Waxman, in separate letters to RNC Chairman Mike Duncan and former Bush campaign chairman Marc Racicot, asked how such e-mails are protected and who has access to them.

“The committee also directs you to preserve all such records because of their political relevance to congressional investigations,” Waxman said.

He noted that separate investigations “have uncovered evidence that White House staff have used nongovernmental e-mail accounts to conduct official business.”

Waxman added that his committee has found evidence “that in some instances, White House officials were using nongovernmental accounts specifically to avoid creating a record of the communications.”