This is an unusually discouraging moment in the Israeli-Palestinian dispute. The peace-seeking efforts of two good men -- Shimon Peres of Israel and King Hussein of Jordan -- are coming to naught. Peres is a lame duck and Hussein is, diplomatically, a dead duck. Nothing promising is on the horizon.

The "Jordanian option" -- an Israeli- Jordanian deal -- had been at the heart of American diplomacy since 1982. Washington designed it precisely for Peres, whose Labor party accepts the principle of giving back some part of the West Bank in return for peace. Peres' Likud coalition partners, who are scheduled to take over the premiership in October, do not accept that principle. That shuts the window on the Jordanian option.

The Reagan administration had anticipated the advice on timing offered by William Quandt in his new book on what might be called the old Egyptian option, "Camp David: Peacemaking and Politics." A second-term president, says Quandt, should make his Middle East move in his first year and a half -- before midterm elections and his own lame- duck status close in.

Reagan did this, putting the State Department out front. Assistant Secretary Richard Murphy carried the burden of an effort to arrange a formula for Palestinian representation that Arabs would credit and Israelis would tolerate -- the twin essentials.

Many people thought it was a fool's errand. Still, President Reagan granted his diplomats authority to offer Palestinians, in return for their agreeing to make peace with Israel, a political vista brighter than any previously opened to them. Hussein, so often put down as a hedger, went way out on a limb. Peres was ready for the formidable task of finding a majority for a policy that even part of Labor was bound to gag on.

In the end the chain snapped at the weakest link -- the PLO's Yasser Arafat. Failure he and the Palestine national movement can live with. Success is harder. It requires compromise and risk. These are the normal freight of politics, but too many Palestinians -- certainly their leadership -- have come to feel they need not pay it. Now the Palestinians are back to their familiar dead end of killing their moderates and demanding to have it all for sure. Syria, the enforcer of Palestinian debility, has won the round.

An embarrassed Hussein is turning the discussion to unredeemed American pledges to provide arms. He needs the political and military bolstering of an arms connection to Washington. He has earned it. He met Peres at least halfway. He is a friend of the United States and no enemy of Israel.

Yet the Israel lobby opposes the deal, and in its characteristic fervor and narrowness can perhaps dictate to Congress. In general, the lobby does not so much assure Israel generous American patronage, which would and should come anyway, as make the hard line a far more appealing Israeli option than it would be on its own. By my way of thinking, this makes the lobby a burden on Israel. On the specific question of arms sales to Jordan, the lobby neglects the American interest, which is to avoid humiliating a friendly, helpful Arab government.

Perhaps nothing can save the Palestinians from themselves. They make heroes of killers, prefer slogans to choices and lend themselves to the designs of Syria, patron of the Palestinian groups that boasted of the recent murder of the West Bank mayor. They are in effect the partners of the hard- line Israelis.

But Palestinian nationalism remains a fact. The PLO's claim on the loyalties of Palestinians remains a fact. This is demonstrably so, no matter how badly the PLO acts and how deeply Palestinians vex Israelis. The Israelis have it within their power to frustrate Palestinian political ambitions -- legitimate ambitions as well as illegitimate ones. The Palestinians have it within their power to hold Israel indefinitely in a state of siege.

Another new book, "The Siege," by Conor Cruise O'Brien, a serious writer who is warm to Israel, suggests that this is Israel's natural state. He regards the idea of an Israeli-Palestinian settlement as a pipe dream inconsistent with the political and emotional realities on the ground.

Is it so? The Egyptian option reached its outer limits with the murder of Anwar Sadat. With Peres and Hussein willing, the Jordanian option had to be tried, but it has now collapsed. That leaves only the "Syrian option," in which Syria arrives at a table with the Soviet Union behind it and a tame PLO on its knee.

The political calendar -- the euphemism for Jewish political influence in American elections -- points to a general diplomatic respite at least until 1989. It might take everyone that long anyway to figure out where to go from here.