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.