Acquittal on criminal charges

On July 17, 2014, Duffy was charged by the Royal Canadian Mounted Police with 31 offences.^[19] Duffy was acquitted of all charges on April 21, 2016. Ontario Court Justice Charles Vaillancourt ruled: "Mr. Neubauer (the Crown prosecutor) stated that Senator Duffy’s actions were driven by deceit, manipulations and carried out in a clandestine manner representing a serious and marked standard expected of a person in Senator Duffy’s position of trust. I find that if one were to substitute the PMO, Nigel Wright and others for Senator Duffy in the aforementioned sentence that you would have a more accurate statement." The judge ruled Duffy had no choice but to list his Prince Edward Island home as his principal residence, as he had been appointed a senator from that province and was constitutionally required to be resident there. Duffy's "free will" had been "overwhelmed" and he had "capitulated" as a result of the PMO's -- Prime Minister Stephen Harper's office, that is, -- "threatening efforts," the judge said. The Superior Court judge said Duffy had been pressured by senior members of the Prime Minister's staff to admit to improper expense accounts when they were, in fact, legitimate, adding "the real deceit came from Harper's office."^[20][21] Robert Fife, now the Globe and Mail's Ottawa bureau chief, won an award for his reporting on the so-called "Senate scandal." On the day Sen. Duffy was acquitted, Fife claimed he had been repeatedly misled by the Harper PMO. He went on to declare the scandal was a "manipulative hoax" by Nigel Wright foisted on the Canadian public. "From the beginning when I broke that story on the $90,000. The Prime Minister’s Office every step of the way lied to me, they lied to Canadians. And inch by inch we were able to scale back and find out one lie after another, one lie after another. And then in the summertime when Nigel Wright and the other key lieutenants in the Prime Minister’s Office were put on the stand, we saw just how this manipulative hoax was put on the Canadian public."^[22] Duffy immediately resumed his seat in the Senate and sat as an independent until his retirement.

Civil lawsuit

On August 24, 2017, Duffy filed a lawsuit against the Senate and the Royal Canadian Mounted Police seeking damages of CA$8 million. Duffy alleged the RCMP was liable for negligent investigation. He accused the Senate of abuse of process and breaching its duty to provide him with a fair hearing before suspending him. Duffy accused the Senate of acting under media pressure and adding to stress that took a heavy toll on his health.^[23]

In December 2018, the Ontario Superior Court dismissed Duffy's lawsuit against the Senate. The decision by Justice Sally Gomery included this statement: "Allowing a court to revisit the Senate's decisions at issue here would interfere with the Senate's ability to function as an independent legislative body, equal to other branches of government". Duffy's suit against the RCMP, based on alleged negligence in their investigation, was not affected by this decision.^[24]

In January 2019, Duffy filed an appeal to the Ontario Court of Appeal.^[25] His appeal was ultimately unsuccessful. In October 2020, Duffy filed an appeal to the Supreme Court of Canada,^[26] which was dismissed in February 2021.^[27]