Debate will continue after Nelson inquiry
Back in September last year this blog noted the difference between the definition of collusion adopted by the Canadian judge, Peter Cory, and the Maclean inquiry into Billy Wright.
Judge Cory included collusion by omission: the authorities turning a blind eye to something.
Judge Maclean opted for the more restrictive definition of collusion by commission: people in authority deliberately agreeing to commit unlawful acts.
The Rosemary Nelson inquiry team chose not to take a view on this discrepancy.
Instead they called the facts as they saw them, concluding there was no evidence the state directly facilitated the lawyer's murder.
However, the inquiry admonished RUC officers for legitimising Mrs Nelson as a target and accused both the RUC and NIO of failing to offer her adequate protection.
With the inquiry team declining to opt for any particular definition of collusion, the politicians have taken up the cudgels.
The TUV leader Jim Allister interpreted the outcome as a "no collusion finding", which in his view will "finally lay to rest another republican myth."
By contrast, the Sinn Fein President Gerry Adams, referring to Judge Cory's definition, argues that the findings amount to collusion on a number of grounds.
This debate will no doubt continue in and around the publication of the report of the inquiry into the murder of Robert Hamill, the Catholic man murdered in Portadown back in 1997.
The inquiry's terms of reference, like the Nelson probe, also cover both wrongful acts and omissions.
However, we won't see the outcome of the Hamill inquiry for some time - until after any potential court cases related to the killing have been dealt with by the courts.
Beyond the debate over defining collusion, will any lawyers representing paramilitary suspects in the future be subjected to the kind of vilification encountered by Rosemary Nelson?
The inquiry team points to reforms such as the video recording of police interrogations, the creation of the Police Ombudsman's office and the transition from the RUC to the PSNI.
If similar complaints about police officers making threats against lawyers were to be raised in the future, the inquiry team thinks they would be more adequately investigated.
A defence lawyer tells me that the recording of interviews has halted the previous pattern in which detectives were accused of threatening lawyers during conversations with their clients without a solicitor present.
In recent years, some lawyers have taken actions against police officers, accusing them of trying to undermine their credibility in politically charged cases.
However, these incidents seem far more the exception than the rule - in contrast to the more widespread complaints logged back in the 1980s and 1990s in cases like that of Pat Finucane.
It is clear some in the RUC took the view that if Rosemary Nelson wasn't for them, then she must be against them.
It's easy to imagine how emotions must have run high, for example, in the wake of the murders of Constables Johnston and Graham in Lurgan in June 1997.
Just as the public want those who murdered Ronan Kerr brought to justice today, so there was great pressure on the RUC 14 years ago to find those responsible for the assassination of two police officers at close quarters.
Perhaps some hostility is inevitable between police officers seeking to put suspects behind bars and defence lawyers trying to ensure their clients walk free.
Northern Ireland wouldn't be the only place in the world where relations between either side aren't exactly rosy.
There have been occasions on which not only detectives, but also defence lawyers have stepped over the line - the decision by the solicitor Manmohan "Johnny" Sandhu to plead guilty two years ago to inciting loyalists to kill, was a particularly shocking example.
However, in the vast majority of cases lawyers are simply trying to do their jobs, and without them the court system would grind to a halt.
So it's important both the police and and defence lawyers respect proper professional boundaries.
If either side crosses the line or allows emotions to take over, it's a recipe for rough justice, or, in the extreme case of Rosemary Nelson, even more tragic consequences.