I have been thinking a lot about Tony Blair recently, not just because I'm a Labour member. I have been thinking about him with my Labour hat on, but also with my Jewish heart.

Because we Jews have lost a lot of votes recently. I am referring to the increasing success of Boycott Divestment Sanctions (BDS) of Israel movement. Most recently, it was passed at the National Union of Students, but BDS is now the official policy of the three biggest unions - Unite, Unison and GMB.

I doubt that BDS will turn Israel doveish, and it hasn't dented UK-Israel trade. But it will make Jewish communal life in this country increasingly difficult.

Shops selling Israeli food, visiting Israeli academics and arts organisations, and cultural festivals have all faced pressure.

The question is, given the escalation we have seen in recent years, where does it end? The claim of BDS proponents is that it is only directed to companies involved in Settlements and East Jerusalem. But given how both these areas are integrated into Israeli life, it is hard to see where the line is drawn.

'People on the left believe they can ‘solve’ things'

We are a long way from the point of no return. But the clock is ticking. If we do not act in time, then any visit to a kosher shop, or activity in a Zionist youth group, or celebration of Israel, will risk political picketing and campaigning - an intolerable strain on the UK Jewish community. At what point will the spotlight turn to synagogues?

So back to those votes. Why do we keep on losing them? When leading Labour lights - such as current leadership hopefuls Andy Burnham, Liz Kendall and Yvette Cooper - try to answer this for their party, they usually either "tickle the party's tummy" or "take it to some uncomfortable places".

It's usually the ones who are willing to embrace the uncomfortable that are proved correct. So that's what we need to do. It's time to break out of our comfort zones.

The most comfortable of political comfort zones is to believe that those who vote for your opponents must be wicked or stupid. Labour members are particularly prone to this. Meanwhile, opponents of BDS often assume that almost everyone who votes for it is antisemitic.

I am sorry, but I doubt it. Those unions have passed BDS motions at conferences with hundreds of delegates representing thousands of members. There are BDS activists who have plunged into antisemitism but we delude ourselves if we think that is what is motivating most of the voters.

So what is? Blair's great lesson to Labour was to understand what made voters tick. In this case, the voters are the members of the British Left. What makes them tick?

I hate generalising about the "left" and the "right", as you can't fit millions of people into one box. However, I do recognise some general characteristics.

Some are values which you may disagree with, but are entirely legitimate. Others are flaws that you may not have - but then again I could write a column on the flaws of the right.

Firstly, the left prizes civil rights over security. So the humiliation that is experienced by Palestinians at checkpoints cannot be justified by continued fears of terrorist attack. There is no argument you can make to most lefties to justify there being de facto Jewish-only roads and Arab-only roads on the West Bank, especially when those Jewish-only roads are in a far better condition.

Secondly, leftists tend to explain someone's material position by their conditions rather than their choices. So the fact that Palestinians are much poorer than Israelis must be mostly down to how Israeli controls suffocate the Palestinian economy, which in turn is what leads young Palestinians to radicalism.

Thirdly, in relation to a conflict between a white people and a non-white people, the left often automatically sympathise with the non-white people. And, in this conflict, however incorrectly, Israelis are identified as white and Palestinians as non-white.

Feeling enraged yet? Because here comes the kicker. People on the left tend to believe that if there is a "problem" then "something must be done" and that any something is better than nothing. If you add up all of those beliefs, then Israel is responsible for the conflict. BDS is the only campaign to do something about it. And so you vote for BDS.

There is no point trying to change those basic assumptions - you have to work with them. A major reason why we fall into this trap is because officially most pro-Israel groups usually assert a two-state solution. But if that is the aim, the question is asked "Whose fault is it that there aren't two states"? And given the above assumptions, then the answer is inevitably: Israel's.

Instead, pro-Israel groups should campaign for a "Peace of Mutual Consent" - whatever it looks like. Then the question becomes: "Why aren't their majorities for peace on both sides?"

And that has lots of answers. Because Arab citizens, who support doveish parties don't turn out at election time. Because Jews and Arabs go to segregated schools. Because there is not enough economic exchange between Israelis and Palestinians.

The way that you solve those problems is you send numerous Get Out the Vote teams to Israel on election day to get Arabs to the polls. You support mixed schools. You back co-operation between Israeli and Palestinian Trade Unions.

What you don't do is boycott. Because boycotting creates resentment and destroys trust. It does not end the conflict - it is the perpetuation of the conflict.

Many may feel uncomfortable with "pandering" to left activists. But until we offer them a different "something" to deal with the situation, they will back the only "something" going - BDS. And we will pay the price.

I originally argued the point in an article for the New Statesman. I was told by an admirer of the article that donors wouldn't touch anything to do with the left, because Ken Livingstone's endorsement of Sadiq Khan for London mayor had given them the heeby-jeebies. Another told me that the Hasbara movement was simply not ready to let go of the two-state solution.

But while we stay in our comfort zone, the BDS bandwagon rolls on. Tick-tock.