I wonder why he didn't simply use reneging? You could write to him and ask.
Although--one of the definitions of renege is break promise: to go back on a promise or commitment. I was thinking that renunciation might have been a better word for what he may have intended. But I have a sneaking suspicion that neither really is accurate. Renege and renounce both imply--well, mean--actively deciding against something one has previously determined to do. Confess I more skimmed the article than read it, but somehow I don't think all of the writers in Britain did that re: being politically engaged.