Chief Margaret Ackley can no longer serve effectively as the head of the New London Police Department. The only question is whether she resigns or the mayor fires her.

Our preference would be for the administration and chief to reach a deal that settles the chief's grievances against the city and includes her resignation or retirement. Unfortunately, attempts by the administration of Mayor Daryl Justin Finizio to reach a settlement have failed.

On Thursday, Mayor Finizio set the stage for moving to the alternative option of firing the chief for just cause. He suspended Chief Ackley and announced an investigation into her conduct as chief. It is clear Mayor Finizio expects to build a case for her removal.

It is a perilous step. In requiring proof of "just cause," state law sets a high standard for firing police chiefs. The intent of the requirement is to assure police chiefs will not be pressured by politicians from fulfilling their duties to investigate crimes, even when those investigations become inconvenient for special interests.

Firing Chief Ackley will invite more litigation. Yet, if the chief is not willing or able to reach a departure deal, it is the only alternative.

An exchange of emails between Chief Ackley and Mayor Finizio in the days leading up to the Sailfest festival - available on www.theday.com - shows the level of dysfunction. Pointing to a communication by a captain in the department, Chief Ackley questions if city police can provide adequate police protection, given the large staff reductions the department has faced in the past couple of years. She raised the possibility of cancelling the event, the largest annual festival held in the city.

In email responses, the mayor offers to help provide additional resources, including contacting the governor to secure more state police help and exploring the hiring of private security. The chief's email responses are at times flippant.

"Private security hiring is not what we do," writes Chief Ackley, even though her captain had recommended that option. In another instance, the chief tells the mayor she is "disappointed" in him for failing to attend an emergency planning meeting.

Who is the boss, here? And didn't anyone think of talking on the phone or meeting face to face to work things out?

The mayor had a chance to hire a new chief after winning the 2011 election. Chief Ackley had reached a deal with the prior administration, under the old city manager system, to depart. But Mayor Finizio - who had benefitted politically when Chief Ackley accused one of his opponents, a city councilor, of meddling in her department - struck a new deal to keep the chief in place.

It has not gone well.

The City Council refused to approve the Ackley deal, which called for a $110,725 salary and a $25,000 settlement of her claim against the former councilor. In June 2013, she sued the mayor and city for reneging on the contract. Last Wednesday she sought an injunction to prevent the mayor from usurping her authority.

On Thursday, Mayor Finizio responded by suspending the chief and opened the investigation into allegations she had undermined contract negotiations with the union, boosted overtime without cause, and unfairly targeted union leaders for discipline.

For the good of the city this tit-for-tat has to end with a permanent change in leadership of the NLPD. It is in the best interests of both sides to seek an amicable path to Chief Ackley's exit. Unfortunately, we doubt that will happen.