The author makes some excellent points.
The record of Britain’s Labour leader is worse than dismal. No one imagines him as prime minister — not even, probably, Mr Corbyn.
Labour was always going to have problems during this parliament, not least because of the dreadful legacy of its last leader Ed Miliband who led it to needless defeat at the 2015 election. Mr Corbyn has since transformed a difficult position into a desperate one.
Mr Corbyn’s career has been lived on the far left fringes of politics, where ideological orthodoxy comes well ahead of a serious desire to wield power. He has never forgiven Tony Blair for winning three elections.
Mr Corbyn said he backed Remain. And then did nothing to prove the point
Some say Mr Corbyn’s weakness has left Mrs May one of the most powerful prime ministers of modern times. In matters European, the reverse is true. The absence of a credible opposition has left the prime minister a prisoner of those on her own side set on severing all ties with their own continent
I must admit almost all of that was predictable when he won the leadership.
I think the most relevant parallel with recent "common sense", or lack of it, decisions would be by calling him, not Mr Corbyn, but Labour McLabourFace.