Democratic vice-presidential nominee Joe Biden said earlier this week that he and running mate Barack Obama could pursue criminal charges against the Bush administration if they are elected in November.

Biden's comments, first reported by ABC news, attracted little notice on a day dominated by the drama surrounding his Republican counterpart, Alaska governor Sarah Palin.

But his statements represent the Democrats' strongest vow so far this year to investigate alleged misdeeds committed during the Bush years.

When asked during a campaign event in Deerfield Beach, Florida, whether he would "pursue the violations that have been made against our Constitution by the present administration", Biden answered in the affirmative.

"We will not be stopped from pursuing any criminal offence that's occurred," he continued, going on to praise congressional committees for the deliberate pace of their inquiries into alleged Bush administration misdeeds.

Members of Congress are "doing the right thing, they're not making false accusations about anything … they're collecting data, subpoenaing records, they're building a file", Biden said.

"If there has been a basis upon which you can pursue someone for a criminal violation, they will be pursued – not out of vengeance, not out of retribution, out of the need to preserve the notion that no one, no attorney general, no president -- no one is above the law."

Obama sounded a similar note in April, vowing that if elected, he would ask his attorney general to initiate a prompt review of Bush-era actions to distinguish between possible "genuine crimes" and "really bad policies".

"[I]f crimes have been committed, they should be investigated," Obama told the Philadelphia Daily News. "You're also right that I would not want my first term consumed by what was perceived on the part of Republicans as a partisan witch hunt, because I think we've got too many problems we've got to solve."

When asked about his comments by Fox news today, Biden said he has no evidence that criminal charges would be warranted and no intention of pursuing action against the current president.

"What is true is the United States Congress is trying to preserve records on questions that relate to whether or not the law has been violated by anyone," Biden said, adding: "But, you know, there's been an awful lot of unsavoury stuff that's gone on. And the mere fact … that it occurred in a previous administration doesn't mean [a subsequent] Justice Department, if, in fact, there's evidence, shouldn't pursue them. "But I have no evidence of any of that. No one's talking about pursuing President Bush criminally."

Congressional Democrats have issued a flurry of subpoenas this year to senior Bush administration aides as part of a broad inquiry into the authorisation of torturous interrogation tactics used at the Guantanamo Bay prison camp.

Three Bush White House veterans have been held in criminal contempt of congressional committees for refusing to respond to subpoenas in an inquiry on the firing of federal prosecutors: former counsel Harriet Miers, former political adviser Karl Rove, and current chief of staff Josh Bolten. The battle over Miers's and Bolten's testimony is currently before a federal court.

· This article was amended on Thursday September 4 2008. We originally omitted the word 'administration' from our headline. This has been corrected.