Sept. 19, 2008 -- An internal government document obtained by ABC News appears to contradict Sarah Palin's most recent explanation for why she fired her public safety chief, the move which prompted the now-contested state probe into "Troopergate."

Fighting back against allegations she may have fired her then-Public Safety Commissioner, Walt Monegan, for refusing to go along with a personal vendetta, Palin on Monday argued in a legal filing that she fired Monegan because he had a "rogue mentality" and was bucking her administration's directives.

"The last straw," her lawyer argued, came when he planned a trip to Washington, D.C., to seek federal funds for an aggressive anti-sexual-violence program. The project, expected to cost from $10 million to $20 million a year for five years, would have been the first of its kind in Alaska, which leads the nation in reported forcible rape.

The McCain-Palin campaign echoed the charge in a press release it distributed Monday, concurrent with Palin's legal filing. "Mr. Monegan persisted in planning to make the unauthorized lobbying trip to D.C.," the release stated.

But the governor's staff authorized the trip, according to an internal travel document from the Department of Public Safety, released Friday in response to an open records request.

The document, a state travel authorization form, shows that Palin's chief of staff, Mike Nizich, approved Monegan's trip to Washington, D.C., "to attend meeting with Senator Murkowski." The date next to Nizich's signature reads June 18.

In response to inquiries about the document Friday, the McCain-Palin campaign provided a statement from Randy Ruaro, another aide to Palin.

According to Ruaro, Monegan asked for -- and received -- approval for the travel without telling Palin's staff his reason for going. "As a matter of routine, the travel was approved by Mike Nizich ... weeks before the actual purpose was made clear by former Commissioner Monegan," Ruaro wrote.

"When you receive permission to travel, it does not mean that you receive blanket authorization to discuss or do whatever you would like on that trip," he added.

Last week a legislative panel approved a subpoena for Nizich to be interviewed by Stephen Branchflower, the prosecutor hired to conduct the Alaska Legislature's inquiry into Troopergate. The Attorney General informed the Legislature earlier this week that Nizich and other state employees subpoenaed in the matter would not submit to interviews.

Nizich did not respond to a message left Friday afternoon.

In Palin's court filing Monday – to stop an investigation by her state Personnel Board she earlier had requested – her lawyer, Thomas V. Van Flein, included numerous emails from her staff expressing confusion and incredulity over Monegan's planned D.C. trip. None of those emails were sent by or to Nizich, although he was cc'd on several.

Contacted Friday, Monegan confirmed the travel authorization was to pursue funding for the anti-sexual-violence program. He said the travel authorization form was completed in a fashion consistent with practice, even though it showed no expenditures. The signed form approved the travel, he said, and authorized him to use a government credit card or seek reimbursement for expenses he incurred during the trip.

Monegan said he didn't know why Palin's chief of staff approved a trip that confounded her other aides. "It sounds like it's a breakdown of communication internal to the governor's staff," he said.

Click Here for the Investigative Homepage.