Garcia, who testified in federal court about his involvement in an alleged kickback scheme with State Treasurer Robert Vigil and another former treasurer, contends in the filing that "political gain, rather than an attempt to see that justice is done, is the motivation behind this prosecution." In June, Madrid took the unusual step of issuing state indictments against Garcia and three other witnesses in the case, even though they have already signed federal plea bargains or immunity deals in exchange for their testimony about Vigil.

Vigil's first trial on racketeering and extortion charges ended in a hung jury. His second trial is scheduled to begin next week.

In a statement, Madrid's office rejected Garcia's claims, saying Garcia's lawyer was trying to "defend his client against the State's charges by attempting to turn the prosecution into a political spectacle." Madrid's campaign has pointed to the prosecutions as evidence of Madrid's tough stance on corruption.

Wilson ads have called the prosecutions a "reckless political stunt" that could jeopardize future federal corruption investigations by making people less likely to accept deals for their testimony. They have also suggested that Madrid should have acted earlier to investigate corruption, claiming she ignored a 2002 letter from a whistleblower about corruption in the treasurer's office. Madrid has disputed whether the letter was ever sent.

Despite the ads, a poll released last week shows Madrid in a virtual tie with Wilson. The poll, conducted August 17-20 by the Democratic pollsters Lake Research Partners, shows Wilson with 46 percent of the vote, Madrid with 44 percent of the vote, and 10 percent of voters undecided. The results closely paralleled a January poll, which found 44 percent of voters preferred Wilson and 43 percent preferred Madrid.

Wilson's campaign declined to comment on the poll, while Madrid's hailed the results as a success.

"Heather Wilson dumped hundreds of thousands of dollars into negative attack ads for more than a month," said Madrid spokeswoman Heather Brewer in a statement. "But New Mexico voters are clearly more interested in issues ... than in mudslinging."

If Garcia's motion is granted, a hearing would be held that could include testimony from Madrid. Hank Farrah, Garcia's attorney, said he did not know when a decision would be reached.

--Will Sullivan