ABC News' Michael Falcone reports:

The George W. Bush Presidential Library has denied a request by a Democratic super PAC to turn over documents relating to Rob Portman's stint in the Bush administration.

Earlier this week the super PAC, American Bridge 21st Century, submitted a Freedom of Information Act request to the Bush Library in Lewisville, Tex. for a variety of records, including correspondence and travel logs that would shed light on Portman's work as director of the Office of Management and Budget and U.S. Trade Representative under the second President Bush.

But in a June 20 letter, Brooke Clement, the supervisory archivist at the Bush Library, which is run by the National Archives and Records Administration, rejected the request.

Clement cited provisions of the 1978 Presidential Records Act stipulating that such records are not subject to Freedom of Information Act petitions until five years after the records agency takes control of the documents or until "processing and organizing" of the records is completed "whichever is earlier."

"If you would like to contact us again on or after January 20, 2014, we would be happy to assist you with your FOIA request," Clement noted in the letter, which emphasized that the library had no legal obligation to release the records early.

Portman, now an Ohio senator and top Republican vice presidential contender, served for two years in the George W. Bush administration as well as during former President George H.W. Bush's White House years.

According to a copy of the FOIA request, provided to ABC News by American Bridge, the super PAC asked the library to provide correspondence, including "copies of all letters, emails, faxes, phone-texts, and memorandum submitted to-and-from Portman from January 2001 to January 2009." The group also requested nomination papers, travel logs and itineraries, White House vehicle expenses and logs, plane expenses and logs, personnel records, letters of reference and lists of White House gifts.

American Bridge was formed primarily as a tracking and research organization. During the primary season the group dispatched operatives to primary states armed with video cameras to record the Republican candidates' every word. Since then, they have been taking a closer look at Romney's record in business and government and have begun doing the same with the presumptive GOP nominee's potential running mates.

"When you look at the roster of V.P. candidates, each of them is significantly flawed," American Bridge senior adviser Ty Matsdorf said in a statement. "For Portman, it is his calamitous record on fiscal issues while working at the Bush White House. It shouldn't be a shock that he is going to want to keep that under wraps for as long as possible, but unfortunately it's pretty hard to hide a record as terrible as that."

The Bush Library did not return ABC News' request for comment.

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