In November 2014 I was arrested, protesting Australia's coal frenzy. I am one of the first IPCC contributors to have taken such a step. At the time, I had already been invited to a meeting in January 14-15, 2015 at the Rockefeller Center in New York, as a reviewer for the Lancet Rockefeller Commission on Planetary Health. Due to my arrest, I was denied the normal US visa, while US consulate lawyers assessed whether my entirely non-violent protest (which carries a maximum penalty, unbelievably, of seven years in prison) constituted "moral turpitude". This application involved an early morning visit to the US consulate in Sydney, the completion of numerous forms and declarations, and the surrender of my passport. Eventually, I was granted a US visa valid for the next 3 months - but, alas, too late to attend the meeting. I made a report instead and prepared some slides (still confidential).
Probably, not visiting the US at this time is a good thing, as it's a long way, and our departure to India is now only 5 days away. My passport, much to my relief, was returned yesterday. If I again visit the US I will need, I'm afraid, to do this all again (ie apply for a visa) - unless the US law is changed.