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The powerful chairman of the House Oversight and Government Reform Committee, Republican Rep. Darrell Issa, today escalated a showdown with the White House over use of personal email accounts to conduct official government business.

In a letter to White House chief of staff Jack Lew, Issa requested the names of all administration staffers who have engaged in the practice, their email addresses and copies of work-related messages sent outside of government email servers.

Congressional Republicans and campaign aides to Mitt Romney have been alleging that members of the Obama White House, including former chief of staff Jim Messina, may have broken federal law by conducting official business through private accounts so as to avoid automatic archiving into the public record.

"The American people have a right to know that White House staff and federal officials are conducting the business of the government transparently and in accordance with record-keeping statutes," Issa writes in the letter. He gave a deadline of Aug. 17 for his request.

Administration and Obama campaign officials insist they have obeyed all federal laws, forwarding business-related email from personal accounts into the White House servers for archiving.

"We all have personal email addresses and for our longstanding relationships, they often use those personal email addresses," said deputy Obama campaign manager and former White House adviser Stephanie Cutter on Wednesday.

"But at the White House we were all instructed for official business to just forward those emails into the White House system. And so that's what we've all done."

Issa, citing Cutter's statement, said the apparent "often" use of private email accounts raises transparency concerns because the onus is on staff to do the forwarding - a practice that is not subject to oversight.

"Unless all emails were forwarded to federal government (.gov) addresses or preserved as paper copies, there is a risk that records subject to the PRA or FRA were not retained as required by law," he wrote.

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White House spokesman Eric Schultz said the administration's general counsel is reviewing the Issa letter and will "respond as appropriate."

"Let's be clear that this is nothing more than a nakedly political, taxpayer-funded effort designed to serve partisan interests, over an issue which House Republicans have already conceded is not serious," Schultz said in a statement.

Democrats have pointed out that Issa and Republicans defended the George W. Bush administration against a similar inquiry in 2008. They also note that a Republican staff memo from the time noted that "the White House is NOT required to preserve and retain every communication or piece of paper ever created" and that "oversight should not be a pretext for congressional micromanagement of executive branch functions."