Sinn Fein is a party with its recent roots in an insurrectionary tradition that sought to smash the State. Many of its leaders are themselves IRA veterans who formed their opinions in jail, or on the run in the last century.
Given that back story, it may be natural for the party to harbour a suspicion that the police and justice system are politically driven.
Such paranoia is misplaced in Northern Ireland, where we have one of the most regulated police services in the world. It is damaging and cynical for a party to act on such suspicions when it is both in Government and on the Policing Board.
We have seen the attitude of the IRA veteran, his easy assumption that the police are political pawns, before.
We saw it when Gerry Kelly, Sinn Fein justice spokesman, attempted to block a police vehicle, proclaiming that he was a member of the Policing Board.
We saw it when Bobby Storey asked, at a rally in support of Mr Adams: "How dare they arrest our leader."
A shared society is impossible while such "us and them" thinking persists. It is deeply damaging to single out distinguished officers like ACC Drew Harris, and blame them for investigations which happen to impact on a politician.
Gerry Adams' arrest came at a legally indicated point in an investigation, after six others had been charged or had files on them sent to the Director of Public Prosecutions.
Mr Harris may attract hostility because he is a former uniformed member of the RUC, as anyone with 30 years' policing experience here must be.
That is unfair. We see Barra McGrory, once an effective defence solicitor for many republicans including Mr Adams and Martin McGuinness, performing with equal distinction in his new role as Director of Public Prosecutions.
It is healthy for people to take on new roles in new circumstances, and both Mr Harris and Mr McGrory can act as role models for others in this respect.
Sinn Fein itself expects former prisoners to be allowed to find new roles and not simply typecast. It should extend the same courtesy to others.
To be fair, it is not the only party that blames the police and makes it personal when they do their duty and that doesn't suit politically.
We have seen a similar attitude from some unionists over flag protests and loyal order parades.
Partisan criticism from two sides like this puts the police in a no win situation and it must cease.
Hopefully, officers like Mr Harris will continue to have the courage to resist overt political pressure. It must at times be tempting to apply for a job elsewhere, but we need them here.