Why is Labour finding it so difficult to shake off accusations of antisemitism?

Politics Explained: Journalists keep finding things in Jeremy Corbyn’s recent history that require strenuous explanation

To the intense frustration of Jeremy Corbyn’s supporters, the accusations of antisemitism against him and the Labour Party refuse to go away.

Although party members continue to be suspended and expelled by Labour’s disciplinary committees, new instances keep coming to light.

And journalists keep finding things in Corbyn’s own recent history that require strenuous explanation. The latest example is his 2011 foreword to a reissue of John Hobson’s 1902 book, Imperialism: A Study.