But it is not so long since anyone - a individual, the Guardian, the bulk of Labour MPs - who expressed less than wholehearted support for Corbyn was met with the question: "Why doesn't X just join the Tories?"
Now one of Corbyn's critics has done just that.
Leon Spence, who was elected as the Labour county councillor for Whitwick in 2013, resigned from the party to sit as an Independent last September when Corbyn was confirmed as party leader.
Today comes news - thanks to the Leicester Mercury - that, after saying he would not, Cllr Spence has joined the Conservatives.
The round here have a fondness for such stunts, but I wonder if they impress voters as much as they think.
If Spence believes that "the country is, on the whole, heading in the right direction under the Prime Minister, Theresa May," you have to ask why he joined Labour in the first place.
Spence, incidentally, writes a column for the Catholic Universe. Will he really vanish into obscurity in a few months time?
I suspect we may not have heard the last of him.