The generally perceived illegality has not been legalised. Far from it. Tuesday’s announcement by the United States of America that it no longer considers Israeli settlements on occupied Palestinian land to be illegal is direly astonishing, indeed yet another instance of irrational diplomacy under Donald Trump.

The paradigm shift will scarcely be able to change international law; but in due course of time, it will be interpreted as approval for expansion, even annexation. In a quirky expression of Washington’s occasionally skewed logic, the decision is seemingly of a piece with US praxis in the Middle East.

Chiefly, assistance to Israel’s right-wing government, the offensive against Palestinians, the virtual abrogation of the two-state solution, the relocation of the US Embassy to Jerusalem, the discontinuation of funding to the UN Palestinian refugee agency, and crucially the recognition accorded to Israeli sovereignty over the Golan Heights.

Small wonder that the Secretary of State, Mike Pompeo’s announcement has swiftly been condemned as the “dismal culmination” of Mr Trump’s record in the Middle East.

Is the announcement on the legality of settlements intended to be a diversion from the impeachment hearings, a diversion that Mr Trump will welcome? One could argue that the Democrats are unlikely to be impressed with the State Department’s latest gambit, which doesn’t qualify as astute diplomacy.

With the Israeli administration in limbo post-election, there is little doubt that the administration actually intends to boost the prospects of Benjamin Netanyahu and bolster the US President’s support among evangelicals.

Netanyahu is clinging on to power as his rival Benny Gantz, who has also welcomed the US decision, struggles to form a rival government.

Yet another Israeli election, the third in less than a year, looks likely, and the attorney-general’s decision on whether to indict Netanyahu on corruption charges is expected very shortly.

The announcement is the latest US challenge to what they call the “rules-based international order”. On closer reflection, the declaration is symbolic rather than practical.

The settlements remain illegal; Mr Trump’s imprimatur does not alter the fundamental position. These settlements have flourished regardless of international strictures.

They have grown exponentially while Barack Obama was President. But the US had at one stage allowed, through a Security Council resolution, a halt to all construction in the occupied territories, rather than veto the same.

On Tuesday, the administration ruffled the feathers of US allies by deviating from decades of policy.

The European Union has swiftly reaffirmed that all settlement activity is illegal, that it erodes the viability of the two-state solution and the prospects for an enduring peace, and that it should be ended.

Democratic presidential candidates were quick to attack the announcement, with Elizabeth Warren pledging to reverse it.

Few will buy Mr Pompeo’s contention that the move will reinforce the likelihood of a peace deal. A single state, most particularly its character, is an uncertain quantity; it will not be both Jewish and democratic.