A fundamental revolution in pro-Israel campaigning is required following the parliamentary vote to recognise Palestine as an independent state.
That is the view of Conservative MP Robert Halfon, who challenged the Jewish community to take a radical look at how it co-ordinates support for Israel.
Pro-Palestinian activists had left Israel supporters standing in their use of social media, he believed.
Mr Halfon was one of the few pro-Israel politicians who spoke during the debate in the House of Commons last week. But as a parliamentary private secretary to the Chancellor George Osborne, he was forced to abstain - rules prevent MPs holding government positions from voting on motions brought by backbenchers.
Following his speech, he received widespread abuse on Twitter - an indication, he believes of how political campaigning has changed. The Harlow MP said Israel supporters had been "outclassed and outgunned by an Olympic mile, especially on social media. The Jewish community was virtually invisible. We are losing the battle.
"I had 400 trolls online, loads of antisemitism, loads of Arabist groups trolling me, and they were active all the way through the debate."
Mr Halfon is highly regarded as one of Parliament's most effective campaigners. He said Jewish communal organisations had failed to move with the times.
"The current way of doing things is like being stuck in the 1970s. It costs very little to create an army of volunteers on Twitter.
"Millions is being raised for good causes at dinners, but actually sometimes this stuff does not cost a lot of money. We need people who understand how this works.
"The pro-Israel lobby should have been tweeting in their thousands, thanking MPs who had stuck their necks out, rebutting nonsense from the other side."
Among the proposals from one professional Israel advocate reflecting on the debate's fallout this week was the creation of an "emergency task force" in the style of the government's Cobra rapid-reaction group. It could be used by communal groups to respond to crises.
But Mr Halfon said that approach missed the point. "The response to every problem is to set up another organisation and do more fundraising. We need a radical reappraisal otherwise we will lose the PR battle. We can't just react to emergencies - we need to be doing this all the time," he said.
One Westminster source said Jewish campaigners faced a broader challenge than social media developments: "When it comes to Parliament, communal organisations are nowhere really. They really don't get it."
