Labour realises a red line has been crossed by Paul Flynn
The Paul Flynn affair marks a high-water mark for a particular type of pernicious anti-Zionist sentiment in the mainstream British left.
At least I hope it does.
The Labour MP's use of the classic antisemitic trope of Jewish dual loyalty in the case of the highly-respected young ambassador to Israel, Matthew Gould, was a deeply sinister development.
It was shocking that an otherwise respected MP did not immediately understand the medieval origins of such language.
A question I hear often is: does Ed get it? His staff do
It is now, unfortunately, all too common to find suggestions of a global Jewish conspiracy in discussions of the Middle East, where the international neo-con alliance replaces the Elders of Zion as the universal bogeyman.
Robert Halfon, Mr Flynn's Conservative colleague on the Public Administration Select Committee, was absolutely right to challenge this language as "out of order" in Parliament.
If it is possible to draw anything positive from this sorry affair, it is that the Labour Party has made it clear that such sentiment is unacceptable within its ranks.
Let's hope the intervention of the Opposition Chief Whip, Rosie Winterton, is enough to deter others tempted to peddle ancient lies about Jewish duplicity.
Questions remain about why it took the Labour Party so long to act in this case.
Ed Miliband's office made it clear that such language would not be tolerated, but the Labour Party's first Jewish leader has still not made a public statement about smears against the character of the UK's first Jewish ambassador to Israel from within his own ranks.
"Does Ed get it?" is a question I often hear. The events of the past week suggest that those around him certainly do.
His recent speech to Labour Friends of Israel indicated that he was finally happy to talk about his own family's close relationship with Israel. Those close to him tell me he is still conflicted about the Israel-Palestinian conflict. He is a politician who by instinct wants to find the just and unjust side in any situation.
Sometimes life is more complicated than that, as Paul Flynn could tell him.