Key needs to press for answers on human rights.
Should John Key be going to the Commonwealth Heads of Government Meeting in Sri Lanka? The question seems not to have weighed very heavily on him. This week he gave three reasons for deciding to attend: he says nothing can stop Sri Lanka taking its turn as host, he notes that while Canada's and India's prime ministers are boycotting the gathering, Britain's and Australia's would be there, and he hopes media travelling with him will put Sri Lanka under added scrutiny.
None of those reasons is compelling. Sri Lanka would be a sorry host if hardly any leaders turned up. David Cameron and Tony Abbott no doubt made their decisions for their own reasons, Mr Key should not take his cue from them or anyone else. And the reporters travelling with him might not be able to roam widely.
If any of the press do run foul of the host's heavy-handed methods, Mr Key might be no more critical than he was when Green MP Jan Logie and an Australian colleague were detained for a few hours this week. Sri Lankan officials said the MPs were travelling on the wrong type of visa and Mr Key gave Sri Lanka the benefit of the doubt.
He is right to be going to the summit but he should be forthright in justifying the journey - and should not be afraid to ask some pertinent public questions of his host. Four years ago President Mahinda Rajapaksa's Government brought a decisive end to decades of periodic rebellion by the secessionist force calling itself the Liberation Tigers of Tamil Eelam.
The end was said to be ruthless. Thousands of civilians were cornered by the Government troops or held captive by the Tigers for use as human shields, depending on which side was telling the story. The Government permitted no independent news coverage. Tamils living in other countries, including New Zealand, appealed to the international community fearing a massacre was imminent.
No intervention came. The Government forces triumphed, the rebels were routed and 40,000 civilians are said to have died. The United Nations called for an independent inquiry into the events of the final weeks but the Government has refused to allow it. When a long civil war ends in a clear, if brutal, victory for one side, it behoves the victors to take steps to repair the wounds. This appears not be happening. Mr Rajapaksa's Sinhalese Government is said to have made no effort since 2009 to reconcile the Tamil minority.
Civil rights appear to be deteriorating again. Some reports say hundreds of people have disappeared, journalists are being threatened for doing their job, union leaders and civil libertarians work under warnings and sometimes are roughed up. The Chief Justice has been dismissed for trying to uphold the rule of law.
The question, of course, is whether all of this is enough to warrant a boycott by Commonwealth leaders. A boycott is the Commonwealth's best weapon short of expulsion for upholding the principles in its charter: democracy, human rights, tolerance, freedom of religion and speech, and the rule of law. The Rajapaksa Government appears to be violating them all except democracy, winning elections with ease among conservative rural Sinhalese.
The Commonwealth needs to use its best weapon carefully. A concerted boycott at this stage would be premature. The absence of Canada's Stephen Harper and India's Manmohan Singh speaks loudly enough for now. It is up to those who attend the Chogm to use the occasion effectively. Their host should be left in no doubt that attendance is not approval and all the Commonwealth's principles count.