Ontario Premier Doug Ford and Prime Minister Justin Trudeau are political opposites who right now share something: both face allegations of political interference in the justice system.

Partisans will no doubt disagree on whose alleged political interference is worse: the federal Liberals' handling of the SNC-Lavalin corruption case or the provincial Progressive Conservatives' alleged meddling with the upper echelons of the Ontario Provincial Police.

You can read plenty of analysis throughout cbc.ca of why the SNC-Lavalin affair matters, why the testimony of former attorney general Jody Wilson-Raybould is resonating, and why the Trudeau Liberals are engulfed in a deepening crisis about just how much political pressure they exerted over a criminal case.

Why are Ford's PCs being accused of interfering with the OPP? The government appointed a close friend of Ford to head the provincial police force, and fired a veteran officer who had produced evidence that Ford tried to influence police operations.

Why does it matter?

"The OPP can be called in to investigate provincial politicians, and the citizens of Ontario need to have faith that the OPP is truly independent, above political interference, and free from abuses of power," said Brad Blair, the deputy commissioner who was fired on Monday after a spotless 32-year career with the OPP.

In a written statement Tuesday, Blair said he went public with his concerns about "real and/or perceived political interference" in the force because "the cost of a compromised OPP is too great a price to pay."

OPP deputy commissioner Brad Blair was fired on Monday after a spotless 32-year career with the service. (Ontario Provincial Police)

How Ford's friend got the job

The government announced in November that Toronto Police Supt. Ron Taverner had been chosen to become the new commissioner of the OPP. Taverner is a longtime friend of Ford and his family, and Ford has made no secret of their friendship.

The premier's appointment schedule (obtained by CBC News through freedom of information requests) and social media postings show he met with Taverner three times after taking office last June. There is no evidence that he met even once with any of the other candidates for the OPP top job. Their most recent meeting was Oct. 9, just days before the hiring process began.

Taverner, 72, didn't rise above the level of superintendent in his 50-year career with the Toronto police. That was two ranks below the level to qualify for OPP commissioner under the original job posting. But on Oct. 24, the government altered the posting, lowering the minimum qualifications, allowing Taverner to apply.

The premier's appointment schedule and social media postings show he met Taverner three times after taking office last June. There is no evidence that he met even once with any of the other candidates for the OPP top job. (Grant Linton/CBC)

Blair's evidence of political interference

Blair was a finalist for the commissioner job that went to Taverner, one of only three people who made it to the second round of interviews.

In December, with Ford brushing aside concerns about the Taverner appointment, Blair launched a legal battle over the move, asking a court to order Ontario's ombudsman to investigate.

As part of the court case, Blair has filed evidence suggesting the premier pressured the OPP to do his bidding on two issues, related to police duties to transport and protect the premier.

Documents suggest Ford wanted $50,000 worth of customization work done on a van, including a power reclining leather sofa and a big-screen TV with BluRay player, to allow him to work while travelling around the province.

Blair alleges the premier's chief of staff told the OPP to keep the cost "off the books," something the premier's office vigorously denies. However, Ford's executive assistant sent the OPP an estimate for the work last October using his personal email address.

Mario Di Tommaso is cheered by members of the Toronto Police Service as he leaves police headquarters on his retirement (Toronto police)

Another document filed in court recounts Ford's complaints to one of his OPP bodyguards about the rotating roster of officers assigned to protect him. The email quoted Ford as saying: "It feels like I'm not getting heard, like I'm getting f---ed around by the OPP and I'm getting more pissed off. I'm going to call the commissioner and sort this out."

Submitting those documents to the court triggered Blair's firing. According to the government, he was fired by the nonpartisan public service commission, on the recommendation of the deputy minister of public safety, Mario Di Tommaso.

Deputy minister's role in hiring, firing

Di Tommaso was until last October a veteran Toronto police officer, and Taverner's boss, as a staff superintendent in charge of the central and west field command. The Ford government appointed him deputy minister of public safety in October, making him the top bureaucrat in charge of the OPP.

Di Tommaso is deeply connected to the controversy embroiling the OPP and the government since then:

The OPP commissioner job qualifications were lowered two days after he took over as deputy minister.

He was one of three people on the hiring committee that chose Taverner over Blair.

He issued a formal warning to Blair in December, a few days after Ford accused Blair of unspecified violations of the Police Services Act.

He initiated Blair's firing.

Community Safety Minister Sylvia Jones points to Di Tommaso's position as deputy minister as proof that there was no political involvement in Blair's firing.

NDP leader Andrea Horwath questions that. "The minister claimed she didn't ask why Mario Di Tommaso was doing this," Horwath said Tuesday in the Legislature. "Why would the minister approve terminating an OPP deputy commissioner without seeking any explanation or rationale for the decision?"

Ford was not in the Legislature on Tuesday morning to take questions about the firing of Blair, as he was touring a SodaStream plant in Mississauga. (Paul Smith/CBC)

Is there political interference?

Several elements of this controversy could lead an unbiased observer to conclude there's been political interference in the top ranks of the OPP: chiefly, that Ford's friend Taverner gets appointed OPP commissioner, while Blair, his rival for the job and a critic of the Ford government, gets fired.

The idea that the police force needs to be 100 per cent independent of politicians is more than a theoretical concern in Ontario. The OPP investigated top aides to both former Liberal premiers Dalton McGuinty (over deleting government documents about the gas plants scandal) and Kathleen Wynne (over bribery allegations surrounding a byelection race). Doubts would have clearly been cast over those investigations had a longtime friend of either premier been running the OPP at the time.

Blair's firing and the push to make Taverner chief amounts to "serious political interference with the administration of justice," tweeted former Toronto mayor David Miller on Tuesday.

But Miller, who battled vigorously with Rob Ford on Toronto city council, is in no way a neutral observer.

The Ford government rejects all the claims of undue political influence. PC officials and politicians from Ford on down insist Taverner is well-qualified. They say the process to choose him was independent. They say the $50,000 estimate for van renovations was just an inquiry, and really about saving taxpayers' money on flights. They say it's normal for a premier to have input on his police security detail. They say there was no political involvement in Blair's firing. And they say the firing was justified.

"Mr. Blair breached his duties as both a police officer and a public servant," said Jones in the Legislature on Tuesday. "No one is above the law."

It all comes down to who you believe. Ontario's integrity commissioner is investigating Taverner's appointment. His report — expected in the coming weeks — could put the controversy to rest or ignite it anew.