The offer by Mahmoud Abbas to negotiate a cease-fire between Israel and Palestinians in Gaza comes as crossfire attacks escalate dangerously but the Palestine president does not appear to have the clout with any of the parties concerned to do anything about it.

A bloody week of offensive reprisals by both sides is quickly eroding whatever good will there was at Annapolis to achieve peace by the year's end. Should Abbas decide to turn mediator the attacks will also show how light his political weight is. Abbas is persona non grata in Gaza after June's Fatah-Hamas split. He is ironically better received in Israel but Israel still does as it pleases. And while the US will take Abbas over Hamas any day, it is Israel that will forever enjoy priority in Washington.

Abbas may be virtually powerless, but the problem is not his inability to obtain a truce. It rather lies much more with Israel's having given no indication of a willingness to set aside its policy of imposing de facto realities by force of arms in favor of the search for peace. This means that Israel will perpetually seek to sustain a qualitative superiority, a military superiority in particular, over the Palestinians in Gaza and elsewhere in the occupied territories.

The highly publicized breakout of Gazans into Egypt through the Rafah crossing made it impossible to ignore the collective punishment being imposed on them by Israel's policy of closure and economic blockade.

Israeli leaders justify their shutting of Gaza crossing points and their temporary cut-off of fuel supplies for Gaza's power plant as a response to Qassam rockets fired into Israel by Palestinian activists. They argue that Gazans suffering from blackouts, food shortages or lapsed power for dialysis machines ought to blame Hamas after last summer's seizure of Gaza. Many Palestinians in Gaza may indeed not be in favor of Hamas refusing to stop the launching of rockets into Israel. Even so, they know that Israel is the power imposing an economic blockade and using its military might to achieve the purpose.

Imposing collective punishment on the people of Gaza is not only inhumane; it is also incapable of producing results that benefit Israel or Hamas or Fatah. This punishing of an entire population to change the conduct of its rulers - in this case Hamas in Gaza -- rarely has the desired effect; it certainly has done nothing but aggravate the situation in Gaza to dangerously high levels.

The current siege policy follows a narrow-minded, obtuse military logic. It assumes that if Gazans are subjected to ever worse deprivation, they will eventually prevail on Hamas to stop the rockets falling on the Israeli town of Sderot. Obviously, this has not transpired and probably never will.

Abbas has repeatedly condemned both Palestinian rocket fire and Israeli strikes on Gaza, and has offered to help broker a cease-fire amid fears that the violence could undermine recently revived peace talks. However, his scant influence over the parties assures little progress. A completely failed mission is also possible but that would not be Abbas' fault. There would be no cross-border barrages had Israel genuinely withdrawn from Gaza in 2005, and the attacks will only continue because of Israel's near-hermetic blockade of the territory.