The chief Palestinian negotiator with Israel staked out a new position Tuesday in Washington: “We want to resume negotiations,” said Saeb Erekat, on the basis of President Obama’s recent Middle East address.

There’s just one catch. Erekat, who met Monday with Secretary of State Hillary Rodham Clinton and senior White House officials, said the talks could not begin until Israeli Prime Minister Binyamin Netanyahu formally accepted Obama’s principle that a Palestinian state would be based on Israel’s 1967 border lines, with mutually agreed swaps of territory to accommodate demographic changes.

If Netanyahu “wants to be a partner he has to say it: Two states on the 1967 lines with mutually agreed swaps,” Erekat said. “He has a choice.” Without that declaration, he said, talks would not go forward and Palestinians would proceed with a plan to petition the United Nations for admission as a member state — an initiative that Erekat said would be launched by July 15.

Erekat made his declaration at a luncheon meeting with Middle East experts (and a couple of journalists) sponsored by the Saban Center of the Brookings Institution. Unusually for such an event, he declared his remarks on the record and repeated his formulation about Netanyahu several times. He left little doubt that he was staking out a position in response to the Obama administration’s efforts to restart negotiations — a position that appears aimed less at advancing the process than at deepening the discord between the Israeli and U.S. governments.

“I have no quarrel with the United States. If Mr. Netanyahu says he accepts the two-state solution on the 1967 lines with agreed swaps, he’s on,” Erekat said in his idiomatic American English. He added: “As far as what [Netanyahu] said in Congress, he’s not a partner for peace.” That was a reference to the Israeli leader’s address to a joint session two weeks ago, in which he declared — to a standing ovation — that Israel would never return to the 1967 lines. Netanyahu and Obama remain publicly at odds over the issue.

The new Palestinian position drew a mixed response from the assembled scholars and former officials. One noted that Erekat did not cite an Israeli freeze of settlement construction as a precondition for talks, as Palestinian leaders have for the last two years. Erekat appeared to confirm that the demand had been dropped; it also went unmentioned in Obama’s May 19 speech.

A couple of other participants, however, questioned the Palestinian’s insistence that Netanyahu make a public statement accepting the borders parameter — which, they noted, the Israeli leader was most unlikely to do. Why not, they suggested, simply announce Palestinian acceptance of talks on the basis of the Obama formulation, and let the rest of the world press Netanyahu for his answer? Then it would be clear that Palestinians were serious about negotiations and not merely attempting to drive a wedge between Jerusalem and Washington.

“I heard you,” said Erekat to one such entreaty. Then he repeated his position. “We’re waiting for Mr. Netanyahu to say two states, 1967 lines with agreed swaps. He needs to say it.”

Erekat’s boss, Mahmoud Abbas, has met only twice with Netanyahu since Obama took office. Instead he has played at fanning tensions between the two. When Obama asked in 2009 for a freeze of Israeli settlements, Abbas made it — for the first time — a Palestinian precondition for peace talks. Now he seems to be doing the same with the border issue, while working on the initiatives with which he plans to conclude his presidency — a reconciliation agreement with the Hamas movement and a diplomatic offensive at the United Nations.

Erekat clarified the Palestinian U.N. plan. He said that if negotiations don’t start by July 15, the Palestinians will petition not just for recognition as a state, but for full U.N. membership. In order to do so, he said, a request must be made to the secretary general, who in turn will refer it to the Security Council. Before the General Assembly can vote on the matter, the petition must pass the Security Council without a veto.

That means the United States could block the Palestinians from obtaining full U.N. membership, Erekat said. The General Assembly could still vote to recognize Palestine as a non-member state, but that would give the Abbas government few diplomatic privileges that it does not already possess.

Since the Obama administration is already on record opposing any Palestinian appeal to the United Nations, Erekat was asked what value the leadership saw in taking the initiative. “We need to pursue every possible venue if negotiations are not the option,” he said. “We have no intention to isolate Israel or delegitimize Israel. Our application for admittance is to preserve the two-state solution.”