In the world of presidential records, "withhold" has a specific meaning. It means a former president raises an objection to a document's release and blocks it from being made public. So far, President Clinton hasn't done that.
Here's how it works: When a president leaves office, the records of his administration go to the National Archives. After five years, the records are generally subject to public records requests under the Freedom of Information Act. Professional archivists determine which records should be publicly available, and the current and former presidents are able to review them as well. The former president is given another seven years — in Bill Clinton's case, until 2012 — to review records and claim exemptions.
Under the provisions of FOIA and the Presidential Records Act of 1978, the exemptions include matters of national security and national defense; invasions of personal privacy such as personnel or medical records; federal appointments; proprietary commercial or financial information; and confidential communications between the president and his advisers.
To withhold a document, Bill Clinton would have to assert that a document falls under one of those protected categories.
However, the former president can take as long as he wishes to review the records, and there's nothing to stop him or his designee from being especially slow about reviewing documents he'd rather not see made public. Even if you don't presume such cynical motives, it's true that President Clinton could be making documents available more quickly by speeding up his own review.
We're withholding a True despite Clinton's technical accuracy because most people who hear her statement will take it to mean the former president isn't holding documents back that could be released, and that's not the whole story. We rate it Half True.