The government relied on questionable witnesses and did not meet its burden of proof in the trial of former lobbyist Kevin Ring, the defense asserted in its closing arguments today.

"You've been treated to a case that's been long on slogans -- that's been long on guilt by association," Andrew Wise, Ring's attorney, told the jury. But the government's case "has been very short on evidence."

He recalled the testimonies of four cooperating witnesses who have already pleaded guilty for involvement in the Jack Abramoff scandal: Todd Boulanger and Neil Volz, former lobbying associates of Ring and Abramoff; John Albaugh, chief of staff to former Rep. Ernest Istook, R-Okla.; and Ann Copland, former legislative aide to Sen. Thad Cochran, R-Miss.

Wise referred to the four as witnesses "whose testimony you must have questions about," and he questioned whether Boulanger in particular "was taking this whole process seriously." The cooperating witnesses "had reasons to tell you things that would help them, even if they hurt Mr. Ring," he said.

The defense also contended that the government failed to provide necessary evidence and witnesses to prove Ring's guilt.

Noting that Ring's ties to former Rep. John Doolittle, R-Calif., are "at the core of this case," Wise reminded the jury that "you heard not one word from a single member of that office."

Ring worked as an aide in Doolittle's office before becoming a lobbyist, and Volz referred to Doolittle as Ring's "champion" in testimony. But because the prosecution did not call Doolittle or any of his staffers as witnesses, Wise contended, the true nature of Ring's lobbying relationship with Doolittle's office could not be established.

Throughout the trial, the prosecution has relied largely on e-mails between Ring and public officials and lobbying associates as evidence. But Wise characterized those e-mails as "stupid little pithy jokes and one-line Blackberry messages," and said this evidence "simply doesn't suffice" to meet the prosecution's burden of proof.

The prosecution said in closing arguments this morning that those e-mails show criminal intent in Ring's "own words," but the defense maintained that Ring was sometimes "fibbing to a colleague" in the e-mails in order to get tickets for friends. Because the e-mails do not say "he just did X, and I'm going to give him Y," they cannot be seen as revealing criminal intent, Wise said.

"They want you to presume corruption. That's not how this works," he said. "They can't just take e-mails without context."

The defense did not call any witnesses during the trial, and Ring did not testify, but Wise reminded the jury that it was not the defense's legal responsibility to put on a case.

"It never became the responsibility of Mr. Ring to disprove" the government's allegations, Wise said.