A watchdog has defended investigating the conduct of a Conservative councillor for calling some colleagues "past it " and "useless".
Ombudsman Peter Tyndall said there was a "thin dividing line" between criticism and abuse.
But he said he had to investigate whether the code of conduct had been breached.
Rene Kinzett, last week cleared by Swansea council standards committee, insisted the complaint was "trivial".
He said the issue should not have got as far as the public services ombudsman.
Mr Kinzett, who is Conservative group leader at the council, told BBC Radio Wales' Sunday Supplement: "Councillors, as well as members of parliament and assembly members should be free to give their political judgements, their assessment of the performance of their opponents, because that is what we do.
"We make clear lines of policy differences and without that robustness of debate we may as well not stand for election, we may as well have a dictatorship or independents standing because they're nice people."
Mr Tyndall told the programme: "The guidance I've issued says robust debate is a vital part of democracy, and also individuals and admininstrations must be held to account and that's entirely legitemate.
'Respect and consideration'
"The decision to have a code of conduct and ethical framework for councillors is partly driven by other issues. Many of the cases I deal with, for instance involve individuals manipulating planning law for personal gain, or individuals abusing or bullying officials.
"The issue Rene raises is at what point does legitimate criticism turn into personal abuse."
Mr Kinzett said his criticism of two cabinet members had been "couched in specific terms" and related to peformance of two areas of the council they had a responsiblity for.
He was unhappy the ombudsman had still taken up the issue, before he was cleared by the council's standards committee.
But Mr Tyndall said: "I had to investigate whether the code, which requires respect and consideration for others, was breached. The standards committee then made its decision and I respect that.
"It is a thin dividing line. I make my decisions as to whether to investigate or not based on the experience of standards committees. We only investigate perhaps only one in five of all complaints because either there isn't evidence the code has been broken or such breaches are very trivial.
"There's a real role for leaders, such as Rene, in dealing with this. There's a possiblity many complaints could be dealt wth locally with discussions among members, senior officers and monitoring officers. I will clearly take account of decisions that are taken before deciding on future investigations."
Mr Kinzett, who represents the Mayals ward, said the ombudsman should have thrown out the complaint brought by two fellow councillors.