It does clash. One good explanation is that the contradiction reflects the power struggle within Hamas. Another is that even the group’s “moderates” are courting two audiences at once — ordinary Palestinians and potentially sympathetic governments abroad — and the aims pull in different directions.

Take the “national unity plan” first, as the motives are a fraction more transparent. Ismail Haniyeh, the Prime Minister, part of the “moderate”, pragmatic camp within Hamas, may have reached a deal with the secular Fatah party and others, including the moderate President Abbas.

Details remain unclear, but one point of the 18-point plan calls for a Palestinian state on the West Bank and Gaza territories captured by Israel in 1967. This is, in effect, recognition of Israel’s right to exist, even if not in those stark words. A second point would see Hamas join the Palestine Liberation Organisation, which also acknowledges that right.

From Hamas, which has steadily advocated the annihilation of Israel, this amounts to a dramatic about-turn.

Why? Most likely, because at least some of its leaders reckon that they will win nothing by maintaining Hamas’s isolation from the world. True, they still seem to have solid popular support. Many Palestinians believe that European governments, in particular, have moved the goalposts in refusing to accept Hamas’s victory in democratic elections until it formally recognises Israel.

But isolation will plunge the Palestinian territories into deeper poverty. Without the cash to pay civil servants, any claim to be even an embryonic state will collapse. Few leaders would want that legacy.

Hamas leaders may also reckon that there is room to court international support in parts of Europe, perhaps China, certainly Russia, even if relations with the US are inconceivable.

But even if Hamas nominally shared power with other groups in a new government, in order to court international acceptance, it would be astounding if it did not seek to retain control of that government, having won a majority.

Yet why, then, in the middle of this delicate change of course, seize an Israeli soldier? Many analysts — including some from Fatah — have taken this as a sign of the influence within Hamas of the hardliner Khaled Mashal, based in Damascus. It may not have been something the “moderates” planned, and hardliners may have wanted to undermine the unity plan.

There is no doubt of the popular appeal of the tunnelling operation, as Stephen Farrell, The Times correspondent, described yesterday, in an interview with a tunnel specialist. The militant, from the Popular Resistance Committees, one of the groups behind the raids, argued that attacks on the Israeli military were a powerful psychological weapon.

The kidnapping also appeals to the longstanding Palestinian conviction that they are the victims of double standards: the seizure of this one soldier provokes protests whereas the Israeli imprisonment of Palestinians does not.

Some militants may reckon that Israeli attacks will strengthen this popular support. But as they compete with moderates for the support of ordinary Palestinians, it would be easy for them to overplay their hand.

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