On Troopergate, the vetters spoke with attorneys involved in the case and asked for additional information from what was initially provided, sources said.
Late Tuesday, Palin's office announced that she asked the state's personnel board to review the allegations surrounding her firing of the former public safety commissioner
The campaign says A.B. Culvahouse, the primary vetter, knew about Troopergate, Palin's daughter's pregnancy, as well as husband Todd's DUI from the start.
Nothing has come as a surprise to the McCain campaign, according to sources from within.
By contrast to Palin's short vetting process, former Iowa Gov. Tom Vilsack told ABCNews.com that he was subjected to more than 20 hours of interviews and turned over 30 boxes of documents when vetted to be John Kerry's vice presidential pick in 2004.
"I had four separate interviews, two with [Kerry vetter] Jim Johnson of roughly three hours each. I was interviewed by five lawyers for over seven hours and turned over 30 boxes of materials. I met with John Kerry for 2½ hours just about my background, after he had spent months with my wife and me campaigning in Iowa," he said.
"The process was thorough. It was extensive. And it was substantially more than what John McCain did for Gov. Palin," he said.
Critics contend that the revelations about Palin suggest more about McCain's judgment than they do about Palin's character.
"In an ideal world, you don't want the vetting process to happen post facto," said Chris Lehane, a Democratic strategist and an adviser to Bill Clinton, Al Gore and John Kerry in their presidential campaigns.
"The real question is: Did McCain really know this would come out or is he just learning about it for the first time," he said.
McCain reportedly considered choosing Connecticut Sen. Joe Lieberman, an independent and former Democratic vice presidential nominee, to be his running mate. Given Lieberman's ties to the Democratic Party and abortion-rights position, McCain's advisers reportedly steered him away from that decision just days before he selected Palin.
"This is about decision-making and it is about judgment. This is the first time McCain had an opportunity to make a decision and it shows really poor judgment," Lehane said.
"Ultimately, we still have seven weeks to see how this plays out. Palin still has time to surprise everyone as much as McCain believes she will," he said. "There are debates and time on the trail [ahead]. Anything can happen."
ABC News' David Chalian and George Stephanopoulos contributed to this report.