OTTAWA — After a politically charged trial, a Conservative member of Canada’s Senate was vindicated on Thursday of 31 charges of fraud, breach of trust and bribery. Among other things, the senator, Mike Duffy, had been accused of improperly using Senate expense money to travel to a dog show to discuss Kerry Blue Terrier puppies.

The case against Mr. Duffy, a former television reporter, attracted a high degree of news media attention and fueled criticism of the Senate, whose members are appointed and which has long been one of the country’s least admired institutions.

“This was a resounding ‘not guilty,’” Donald Bayne, Mr. Duffy’s lawyer, said outside court. He added that Mr. Duffy had endured “more public humiliation than probably any Canadian in history.”

By international standards, the amount of money involved was less than dazzling.

At the center of the case was a charge that Mr. Duffy had solicited a bribe from Nigel Wright, the wealthy chief of staff to Stephen Harper, the former prime minister. Mr. Duffy owed more than $70,000 for expenses that had been ruled improper, and, in 2013, Mr. Wright covered the amount from his personal funds.