The reckless killing of at least 16 Palestinians by Israeli army fire at the Gaza border on 30 March, and nine on 6 April, and the wounding of hundreds each time, is likely to be followed by many more clashes.
The organisers of the Palestinian demonstration on the Gaza side of the border fence, and the political-Islamist Hamas, which rules and politically dominates Gaza, plan a series of further demonstrations on Fridays up to the anniversary in mid-May of the declaration of the state of Israel.
The killings were not a new sort of response from the Israeli army. In December, when there were demonstrations on the Gaza side of the border fence over Donald Trump's announcement that he would move the USA's embassy to Jerusalem, Israeli fire killed eight people, including a double-amputee in a wheelchair.
Left-wingers in Israel are demonstrating against the shootings in Tel Aviv on 1 April. Israeli police have recommended that right-wing prime minister Benjamin Netanyahu be prosecuted on corruption charges. But a decision on prosecution is unlikely for months. For now aggressively right-wing forces hold the political initiative in Israel.
Also in May, Trump is set to renounce the nuclear deal with Iran, and to carry through the US embassy move to Jerusalem. On 9 April, John Bolton, an open advocate of US war against Iran, takes office as Trump's national security adviser.
War dangers are looming. To mobilise broadly for peace - and for a political settlement that can allow peace, namely the establishment of a genuinely independent Palestinian state, in contiguous territory, alongside Israel - is urgent.
In the first place that has to be a mobilisation in support of the opposition inside Israel, and for a demand on the Israeli government, which with a huge superiority of military power holds the shots, that it takes the initiative to end its occupation of the West Bank and its blockade of Gaza, and makes way for "two nations, two states".
Last time there were big mobilisations in Britain over the plight of the Palestinians, at the time of Israel's bombardment of Gaza in 2008-9, they were dominated politically more negatively, by anti-Israel warmongering, than by positive efforts to help Palestinian rights. On the big demonstrations, calls to destroy Israel were made by some platform speakers, and explicitly contradicted by none. On a Sheffield demonstration, Workers' Liberty supporters with placards criticising Hamas as well as the Israeli army had their placards and papers seized and ripped up.
With Zionists flying the Israeli flag recently banned by force from an anti-racist march in Glasgow (17 March), and a sizeable body of opinion in the Labour Party saying that protest against antisemitism is nothing but a contrivance to impede criticism of Israel, it will take effort to get a better outcome.
Part of the picture here is the conventional story that the liberal mass media are - and, so it is hinted, because of some conspiratorial manipulation - heavily Israel-biased. Denunciation of the "pro-war, pro-US, pro-Zionist BBC" is commonplace.
From that is taken the conclusion that no scale of denunciation of Israel can be excessive, because it is only counterbalancing what is taken to be a great bias the other way in the mass media.
In fact, the liberal media's presentation of the immediate news of 30 March has been pretty straight, and surely and justifiedly has encouraged pro-Palestinian feeling. In the liberal media's presentation of the background, the lapses and gaps are tilted against Israel rather than for it.
Hamas and its allies made a choice to stage the 30 March demonstration, and the others planned over the coming six weeks, not on the demand that Israel end the blockade of Gaza, not on a call for Israel to concede the Palestinians their right to self-determination in a state alongside Israel, not even on appeals for a halt to Israel's aggressive programme of building new settlements in the West Bank. The choice was to demand "the right of return".
No doubt many Palestinians joined the demonstrations just as the available way to protest against ill-treatment by Israel, rather than choosing that particular demand. But the organisers chose the demand, one that has no potential to bring a democratic settlement nearer.
The media have reported it flatly, as if it were a regular demand by refugees to get back home, or even a regular demand for freedom of movement across borders.
In fact, as we have argued for some time now, the "right of return" has over the decades been a demand by Arab states to reverse the outcome of the war of 1948 and collectively repossess what is now Israel as Arab territory again (with varying provisos about some individual and religious, but not national, rights for the Jews living there).
Redress for the Palestinians who live as refugees today is surely a necessary part of a settlement in the Middle East. It can be achieved by the creation of a genuinely independent Palestinian state, by reparations and aid to that state, by a gradual easing of movement across the borders towards freedom for individuals.
But to try to achieve it by the traditional "right of return" is both hopeless - Israel will never agree to a reversal of 1948, and is strong enough to resist - and unjust: it would mean extinguishing the national self-determination of the Israeli Jews.
The choice of "right of return" as the slogan blocks progress - though it is still surely the case that Israel could gazump Hamas politically by conceding and helping to build a genuinely independent Palestinian state in contiguous territory alongside Israel.
"Right of return" is not a demand for elderly Palestinians to be able to live their last years in their childhood homes, or for those Palestinians who prefer to live in a mostly-Jewish environment rather than an Arab one to be able to choose that. It is an equivalent of the demand by a minority of German right-wingers in the 1950s and 60s for Germany to reclaim territories like East Prussia, solidly German-majority for centuries, from which Germans were expelled in 1945. The freedom of movement which now exists between Poland and Germany is not a version of that "right of return", but became possible only because it had faded from politics.
750,000 Palestinians were driven out or fled from what is now Israel in and around the war of 1948.
In Israel, in 1951, some 220,000 people, about a quarter of the Jews who had arrived there since 1948, also lived in refugee camps. They were mostly Jews who had fled from Arab countries, where a wave of persecution started even before May 1948. A Jewish population of 900,000 across the Arab world - with some large concentrations, for example one-third the population of Baghdad - was successively squeezed out, so only a few thousand remain today.
Five million Palestinians, descendants of the people of 1948, are classed by the UNRWA as refugees today, and 1.5 million live in refugee camps. The reason why they are still classed as refugees, and often have to live as such, while descendants of the German refugees of 1945, or the Jewish refugees from Arab countries of 1947-67, or Greek refugees from Turkey of 1923 and after are not, is not rooted only in Israeli misdeeds of 1948, but also in Arab state policy.
The Arab states made war on Israel but did not help the Palestinians. Jordan and Egypt seized most of the territory allocated by the UN to a Palestinian state - the defeated, dispersed Palestinians were in no position to protest. The Arab states deliberately kept the refugees - and their children, and their grandchildren, and their great-grandchildren - in refugee camps, with refugee status, blocked (to differing degrees) from integrating where they lived. The Israeli government in 1949 made tentative offers to reintegrate some refugees, but the Arab states were unwilling to negotiate, and many of the refugees, too, believed that the Arab states would surely soon re-run the war with a reversed outcome.
The 1948 war is often presented as if it consisted only of the Nakba, the driving-out of Arabs. In fact it came when the Jewish community there, after some years of guerrilla war against the British rulers, and after Britain decided to withdraw and the UN called for Jewish and Palestinian-Arab states side-by side, declared an independent state and five Arab states invaded, seeking to extinguish that state and (some of their leaders said) "drive the Jews into the sea".
From the usual presentation, you would think that everyone on the left would have backed the Arab armies in 1948. They did not. The left saw the Jews as people fighting for some security against the age-old persecution which had recently culminated in the Holocaust, and the Arab states as corrupt tyrannies mostly semi-controlled by Britain. Some on the left backed Israel, some thought it impossible to take sides, virtually none backed the Arab states.
The demand to re-run the 1948 war with an Arab victory next time was not a demand that people on the left made at the time, and has become more, not less, senseless over time.
In 2003 a draft two-states deal, the Geneva Accord, negotiated unofficially but by leading Palestinian and Israeli officials, proposed compensation and limited resettlement for refugee-status Palestinians. It was endorsed by Palestinian leader Yasser Arafat and the then Palestinian Authority prime minister Ahmed Qurei, but Ariel Sharon's Israeli government rejected it out of hand. Then the idea of mutating "right of return" in that way to gain real redress and make peace seemed to gain headway. Bringing the traditional "right of return" upfront again is a new move.
Isn't it pedantic, or even indecent, to discuss this history when Israel is now strong, aggressive, and so callous about shooting down demonstrators?
It isn't - because a solid movement which can really help Palestinian rights can be built only on the basis of a program which is both realistic and democratic, recognising rights on both sides. The need to go beyond simplistic "politics of the last atrocity" - while also responding vigorously to each atrocity, and not just sinking it philosophically into the long run - has become commonplace in discussion of Ireland. We need that on Israel-Palestine too.