Although both President Bush and Sen. John F. Kerry have repeatedly said they have made public their complete military service records, neither presidential candidate has yet permitted independent access to original files held in a high-security vault.

The lack of outside verification of the military personnel records of the candidates has made it more difficult for journalists and historians to evaluate their Vietnam War-era service, which has been the subject of lively election-year debate. In Bush's case, Texas Air National Guard officials have also delayed or prevented public access to 30-year-old unit records that could shed light on whether he received favorable treatment from the Guard because of his father's political connections, as his Democratic opponents have alleged.

More than seven months after the White House announced that Bush's records had been "fully released," files continue to trickle out almost weekly from the Pentagon and elsewhere. Some of the newly released records contradict earlier claims by the Bush camp, such as his assertion in a 1999 campaign autobiography that he gave up flying "because the F-102 jet I had trained in was being replaced by a different fighter."

In the past few weeks, both candidates have been forced to deal with questions about what they were doing in the Vietnam War even as they honed their debating points about Iraq and the war on terrorism.

Assembling a full Vietnam War-era record for the two men is complicated by the fact that the files are scattered around more than a dozen repositories. In addition to master personnel files on each candidate, which are at the National Personnel Records Center in St. Louis, researchers have been looking for the records of the units in which they served. Typically, unclassified unit records are available to the public under much less restrictive conditions than individual files.

Both Bush and Kerry have made public hundreds of documents about their military service and posted them on the Internet. At the same time, they have retained control over their personnel records, making it impossible for outsiders to tell whether anything is being held back.

Chad Clanton, a Kerry campaign spokesman, replied to a request for independent verification of Kerry's master personnel file by saying it was unnecessary "since we've already placed John Kerry's entire military file on our Web site." White House spokeswoman Claire Buchan said yesterday that the White House was "working with the Defense Department to accommodate [The Washington Post's] request to independently verify the completeness of the president's personnel records."

An analysis of records released by the White House and the Kerry campaign shows internal discrepancies that raise doubts about whether the full files have been released. Bush aides have made public two versions of the president's master personnel file, one in 2000 and one this February. Each version contains at least half a dozen pages missing from the other, suggesting that neither is complete.

In Kerry's case, it is difficult to tell which documents on his Web site come from his master personnel file. At least one document first posted on the Web site in August -- a recommendation for a Bronze Star -- appears to have come from his personnel file, contradicting earlier assertions by his campaign that everything in the file had already been made public.

Although the St. Louis repository is under the control of the National Archives, officials at the Archives say that the records belong to the military unit that generated them. In practice, they can be released to outsiders only with the permission of the veteran concerned. Such access is usually granted through the signing of a release known as Standard Form 180, a step that neither candidate has so far taken.

Scott Levins, assistant director for military records at the St. Louis repository, said the National Archives made copies of the candidates' master personnel files before temporarily releasing the originals to other government agencies for inspection and copying. He said these authenticated copies are now locked in a vault and can be inspected only with the permission of the originating agency.

Questions about Bush's military records have centered on how he gained a coveted pilot's slot in the Texas Air National Guard in 1968 and why he gave up flying in 1972, more than two years before his six-year term ended. Kerry critics, meanwhile, have focused on how he won the three Purple Hearts that permitted him to return home early from Vietnam.

In part because Kerry served with the Navy rather than the National Guard, his unit records are much more accessible than those of Bush. The Navy maintains a historical center at the Washington Navy Yard where researchers can freely inspect the records of Kerry's Swift boat outfit, Coastal Division 11. The records include after-action reports and unit histories, which have made possible a detailed reconstruction of Kerry's day-to-day activities.

By contrast, National Guard officials say their Vietnam War-era records are sparse and poorly maintained. Because Bush's unit, the 147th Fighter Interceptor Group, was not an active-duty unit, record-keeping was even more informal than in Guard units that served in Vietnam. Until recently, "nobody was interested" in its history, said Travis Evans, a Texas National Guard freedom-of-information officer who has been deluged by requests to access Bush records.

Even so, the Bush administration has made it difficult for researchers to gain access to unclassified Guard files. For months, all requests relating to Bush's military service were referred to one public affairs officer at the Pentagon, Lt. Col. Ellen Krenke. The Freedom of Information Act officer assigned to the Bush records case, James Hogan, declines to talk directly to reporters.

This week, in response to complaints about lack of access, the Pentagon permitted a Post reporter to inspect records held by the Air National Guard history office in Crystal City. The Post has so far been unable to gain access to more detailed records preserved by the 147th in Houston or the Texas adjutant general's office, including a collection of "special orders" that could shed light on Bush's Guard service.

Most records at the Air National Guard history office are unclassified unit histories releasable to the public. But the Pentagon failed to release the 147th unit history until Sept. 17, more than six months after the Associated Press filed Freedom of Information Act lawsuits for them and five years after reporters first began requesting them.

A Nov. 28, 1999, letter to the National Guard history office from a Texas National Guard historian, Tom Hail, noted that the 147th unit's histories were generating great interest "by the press scouring for dirt on Governor G.W. Bush." He said requests for copies of the documents were being handled through the Freedom of Information Act process. A Guard public relations officer, Col. Tom Schultz, said more research was required to establish what happened to the 1999 requests.

The unit histories undermine the initial contention of the Bush camp that he gave up flying because his services as an F-102 pilot were no longer needed. They show that the F-102 remained the workhorse of the 147th through mid-1972, when Bush moved from Texas to Alabama to take part in a political campaign, even as pilots were being trained on the more sophisticated F-101. Fifteen F-102 planes were in service in the 147th that year, compared with 18 planes in 1968, the year Bush joined the Guard.

The use of F-102s expanded in October 1972, when the group assumed a new "24-hour active alert mission" to safeguard the southern boundary of the United States against "surprise attack," according to the unit history. The new mission required that two F-102 fighter-interceptors be on five-minute alert at all times. The plane was not phased out until September 1974, 21/2 years after Bush stopped flying.

The unit histories also cast doubt on a 1999 statement by Bush that there were "five or six flying slots available" in the 147th when he first expressed an interest in applying, in January 1968. At that time, the unit was two pilots short of its assigned strength of 29 pilots. Two pilots were undergoing training to take over the positions, and one pilot was on the transfer list.

Researcher Alice Crites contributed to this report.