When the political class loses faith in its ability to make moral judgments, what does it do? It calls in the lawyers. The present fashion for judge-led inquiries in the UK has given us the Leveson inquiry into the ethics of the press, and may yet lead to a similar examination of the ethics of banking.

On the moral issue of settlements in the Occupied Territories, Israel and the Trades Union Congress could not be further apart. But they have both resorted to calling in the lawyers to bolster their case. According to leaks in the Israeli press this week, a report by former Israeli Supreme Court justice Edmond Levy will back the view that the settlements are legal, because Jordan did not have sovereignty over the West Bank prior to Israel's occupation of the territory during the Six-Day War. This would fly in the face of the International Court of Justice.

Meanwhile, a legal opinion from James Crawford, professor of international law at Cambridge University, published by the TUC on Monday, found that a boycott of settlement goods by EU countries would be legal. Professor Crawford reasoned that "the EU would not be in breach of its World Trade Organisation obligations since… as a matter of international law, the West Bank and Gaza cannot be considered to be Israel's territory". The opinion stopped short of finding that members of the EU were obliged to ban imports from the Occupied Territories but it gives a boost to the TUC's boycott campaign, and those within the Labour Party pushing the leadership for a tougher line on settlements beyond support for the labelling of goods.

The present UK government has made it clear that it does not support a boycott. Food Minister Jim Paice said the government, "does not believe that a government-imposed ban or boycott of settlement produce would help engage or influence Israel, or lead to progress in the peace process."

It has long been the line taken by the Jewish Leadership Council that it is not helpful to make a fetish of settlement-building, and coalition ministers appear to have accepted this argument. But this is a tactical argument based on political expediency; it does not address the rights and wrongs of occupation and boycott.

Everything in this debate depends on the bona fides of the participants. Did Netanyahu really commission the Levy report to receive a balanced view on the legal status of settlements? Can the TUC seriously be trusted to limit its boycott calls to the settlements?

This is a question of leadership. In the case of the TUC, the news that Frances O'Grady will take over as general secretary is grounds for hope. She is a genuinely impressive trade unionist who does not take the usual knee-jerk positions on Israel.

Ultimately, individuals (including politicians and trades union officials) need to decide what they think, and not sub-contract their moral judgments to lawyers.