Canada's opposition made political hay on Tuesday over letters sent from Justin Trudeau's government to a host of sitting judges, asking that they step down.

Those letters may break federal ethics guidelines, and a possible violation of those rules has led to the opposition Conservative Party calling for minister's head.

The controversy amounts to the first ethics scandal of Trudeau's nascent government, which campaigned heavily on accountability and transparency.

Government House Leader Dominic LeBlanc defended himself Tuesday, telling the House of Commons that "writing to a government official about a specific appointment is different than writing to a government official about a specific issue."

The Conservatives, however, continued to target the government over the letters.

"Political interference is political interference," said Karen Vecchio, Conservative Member of Parliament for Elgin—Middlesex—London, during Question Period on Tuesday. "In the past, this exact issue has caused Liberal ministers to resign."

The issue was flagged to VICE News ahead of the Conservatives questioning of LeBlanc on Tuesday afternoon.

The debacle unfolded after some dubious decisions made by the former Conservative government.

Before calling an election last August, then-Prime Minister Stephen Harper appointed 49 Canadians to various tribunals, boards, and federal jobs, in a move that was decried as old-school patronage. In most cases, however, Harper merely extended or renewed their existing appointment.

Nevertheless, the incoming Liberal government blasted the appointments, which were only discovered after the election. Dominic LeBlanc, who holds the title of Government House Leader and is generally responsible for the Parliamentary functions of the government, issued letters to some of those who received appointments from the previous administration.

LeBlanc sent letters to 33 of the appointees, pressuring them to resign their posts.

"I believe that many of them, if not all of them, will want to do the right thing by Canadians."

"I am therefore asking that you consider voluntarily choosing to not serve pursuant to the appointment approved by the previous government," LeBlanc wrote. He said that, should they resign, they would still be invited to seek the post in an open selection process.

The Conservatives say that sending the letters amounts to an ethics violation that may be grounds for his resignation. They point to a section of ethics and accountability guidelines that set out how government is expected to operate.

"Ministers must not intervene, or appear to intervene, with tribunals on any matter requiring a decision in their quasi-judicial capacity, except as permitted by statute," the rules read.

The letter asks the appointees to contact Mathieu Bouchard, a senior advisor inside the Prime Minister's Office.

"Look, what we've said is the letters that I sent on behalf of the Prime Minister yesterday were not a judgment on particular individuals," LeBlanc told journalists in December. "It was in our view a judgment about a process that did not meet the required elements of transparency in terms of parliamentary scrutiny. We thought that those actions constituted an abuse of process by a previous government."

LeBlanc called their appointments an "abuse of process" by the previous government.

"I believe that many of them, if not all of them, will want to do the right thing by Canadians."

"Judges must be able to make courageous, even unpopular decisions knowing that no one — a chief justice, another judge, a government official or even the most powerful politician — can fire them or cut their salaries as retaliation."

LeBlanc gave the appointees until December 18 to either resign, or decline the appointments outright. The government later said that a "significant number" voluntarily resigned, though they did not offer details.

But while the Liberals objected to the previous government's process, their tactics for remedying the situation may be significantly more grave.

On the list of individuals who were given the appointments, or had their appointment extended in the last days of the Harper government, nearly a dozen sit on boards or tribunals that have legal authority.

And while the Conservatives have defended the qualifications of appointees, they've taken particular umbrage over LeBlanc's efforts to putsch a raft of appointees who deal with citizenship, refugee applications, and pension payments.

Two of those who received the letters sit on the Social Security Tribunal, while two are members of the Canadian Human Rights Tribunal, and five sit on the Immigration and Refugee Board. Roy Wong, who is an actual citizenship judge, was asked to resign from the Citizenship Commission.

The federal government frequently appeals cases to the Immigration and Refugee Board (IRB) and the Citizenship Commission, and both are designed to be arms-length from politicians and bureaucrats.

While the government has the authority to appointment members of those bodies, it is generally discouraged — if not outright forbidden — from becoming directly involved in their work, or interfering in staffing.

The IRB website notes that, barring a problem with performance, the minister is supposed to continue reappointment members.

"The reappointment process for IRB members will continue to reflect a performance evaluation consistent with the merit-based competency criteria," reads the IRB website. "The minister will continue to recommend the reappointment of members…after taking note of the IRB Chairperson's recommendations concerning performance and operational needs."

All of those IRB members who received letters from the Liberal government were re-appointed by the Harper government, not new appointees.

The website for the Canadian Human Rights Tribunal, meanwhile, notes that members may only be removed by the government "for cause." Both members of that board who were asked to resign by LeBlanc had already sat on the tribunal, and merely had their terms extended.

"Governments appoint and pay judges, but once appointed, judges are shielded from bureaucratic control," reads a statement posted on the website of the Canadian Superior Courts Judges Association. "Judges must be able to make courageous, even unpopular decisions knowing that no one — a chief justice, another judge, a government official or even the most powerful politician — can fire them or cut their salaries as retaliation."

Interference with sitting judges or legal bodies has, in the past, led to political fallout.

In 2011, then-Aboriginal Affairs Minister John Duncan resigned his post after it was revealed that he sent a letter to a tax court on behalf of one of his constituents.

"I realize that it was not appropriate for me, as a Minister of the Crown, to write to the Tax Court," Duncan said in his resignation letter.

He's not the only one. In 1990, Jean Charest, then the minister responsible for sports, resigned his post for speaking to a judge over a case involving a sporting association. In 1996, Defence Minister David Collenette stepped down after it was revealed that he sent a letter to an immigration board — the same one that Trudeau's government has sent a raft of letters to — on behalf of a constituent.

Former Finance Minister Jim Flaherty got in a similar pickle after writing a letter to the Canadian Radio-Television and Telecommunications Commission over an upcoming decision, although he did not resign.