A United Nations resolution condemning Israeli settlement building in the West Bank and eastern Jerusalem as illegal is putting the Obama administration in an awkward squeeze — and thrusting two major pro-peace process groups into the tumultuous epicenter of the Middle East debate.

The Obama administration, which is expected to veto the resolution, nevertheless is caught between its own longstanding stance on settlements and political realities at home.

Both J Street and Americans for Peace Now, arguing that the resolution essentially mirrors longstanding U.S. policy on settlements, are calling for Washington not to veto the resolution. The move, apparently an unprecedented action for both groups, is justified by the dangerous deadlock in the region, accelerating settlement activity and the Obama administration’s indecision about what comes next, they say.

“We take this position with great pain,” said Hadar Susskind, political director for J Street. “We share the belief that the UN is not where this issue should play out. The problem is, if Israel is not engaging with the Palestinians in a constructive process and if the U.S. is not leading the way forward, the only option that is left is the international diplomatic option. It’s not what we would like to see happen.”

But J Street’s pain didn’t keep one of the group’s early supporters from breaking with it over the issue.

In a statement, Rep. Gary Ackerman (D-Queens, L.I.) lashed out at J Street’s position, saying it “would effectively and unjustly place the whole responsibility for the current impasse in the peace process on Israel, and — critically — would give fresh and powerful impetus to the effort to internationally isolate and delegitimize Israel…

“I’ve come to the conclusion that J Street is not an organization with which I wish to be associated,” Ackerman said.

(In a statement, J Street leaders said Ackerman’s comment reflects “a misunderstanding of J Street’s position.”)

Major pro-Israel groups argue that anything other than a veto would complicate U.S. peace efforts in the region and send a dangerous message to the Palestinians that the region’s problems can be solved by an international body with a reputation for hostility to Israel, not by direct negotiations.

And some analysts warn that the resolution is meant to serve as a precursor to UN action recognizing a Palestinian state not created through direct negotiations with Israel.

“This is only the appetizer, getting ready for the main course,” said Aaron David Miller, a longtime State Department official who advised administrations on Middle East peace efforts for more than two decades. “It’s part of a strategy to see if [the Palestinians] can get sanction for a much more ambitious resolution. Something on the parameters of Palestinian statehood will be next.”

The tussle over UN action is taking place against the backdrop of startling, if not conclusive, revelations in the Palestine Papers — a mountain of leaked documents dealing with some of the internal communications of the Palestinian delegation in talks with Israel at the end of the Ehud Olmert government.

Those documents seem to point to a Palestinian side that was more open to direct bargaining on most of the major issues separating the two sides and more willing to offer compromise solutions than Israel — or the Palestinian Authority — has admitted. But they also point to a vast chasm between what Palestinian negotiators say privately to their Israeli counterparts and the maximalist positions they take in public.

It also comes as analysts dissect last week’s release by the Washington Institute for Near East Policy (WINEP) of proposed maps for an Israeli-Palestinian agreement on borders. The maps suggests several possible scenarios that would allow Israel to keep the maximum number of settlers in major settlement blocks while giving the Palestinians — with land swaps — the equivalent of 100 percent of the West Bank.

The proposal by WINEP’s David Makovsky breaks little new ground, but is remarkable because of its provenance; the group has strong ties to the pro-Israel lobby, and Makovsky enjoys the confidence of a broad spectrum of Israeli leaders, as well as top Palestinian officials and U.S. policymakers.

The UN resolution, promoted by the PA and the Arab League, is explicit in stating that “all Israeli settlement activities in the Occupied Palestinian Territory, including East Jerusalem, are illegal and constitute a major obstacle to the achievement of peace on the basis of the two-state solution.”

It goes on to condemn settlement activities “aimed at altering the demographic composition, character and status of the territory.”

None of that is outside the longstanding parameters of U.S. policy, said Ori Nir, spokesman for APN.

“Our understanding is that its drafters made a strong effort to keep the language of the resolution within the boundaries of what is known to be U.S. policy,” he said. “So for the U.S. to veto it would be to veto its own policy, in a way.”

Groups like APN insist that with Israel accelerating settlement construction since the failure of U.S.-led efforts to extend last year’s settlement moratorium and with Prime Minister Benjamin Netanyahu’s toughened line on Jerusalem, the Palestinians were left with little choice but to appeal to the international body.

And they say the shock of a U.S. decision not to veto the resolution might be enough to convince the Netanyahu government to curb settlement activity even if it doesn’t agree to a formal freeze.

But other leading activists say not vetoing any final resolution would be a big mistake that would just harden the positions of Netanyahu.

Former peace negotiator Aaron David Miller said claims that a non-veto would press Israel to limit settlements and come back to the negotiating table are “bad arguments. While I’m no fan of settlement activity, there’s nothing here of value for the Obama administration. They have to remain steadfast against Palestinian efforts in New York.”

A decision not to veto, he said, would send a dangerous message to the Palestinians that they can expect “shortcuts or imposed solutions through a UN mandate.”

And after the recent departure of Labor from Netanyahu’s coalition, a decision by the Obama administration not to veto a settlements resolution could just stiffen Netanyahu’s resistance and undercut pro-peace process forces in Israeli politics.

The UN resolution comes as the Palestinians ratchet up efforts to win diplomatic recognition, or at least enhanced diplomatic status — an effort that has produced strong results in Latin America and hints of more in Europe; this week Ireland became the first nation to upgrade the Palestinian diplomatic mission to the status of an embassy.

Miller warned that the pending resolution is likely a precursor to efforts to win more extensive UN action on the parameters of Palestinian statehood.

And then there’s partisan politics.

With Republicans ascendant in Congress and eager to depict the administration as hostile to Israel, “there’s absolutely no way the administration will regard picking another fight with Israel on settlements — particularly using the UN — as a smart political move,” said a longtime pro-Israel lobbyist who asked that his name not be used. “I understand there have been discussions about whether or not to use the veto within the administration, but I’m certain political factors will convince them to do what we’ve always done and veto a one-sided resolution.”

Last week Secretary of State Hillary Clinton seemed to signal that the administration was leaning in that direction, saying, “We don’t see action in the United Nations or any other forum as being helpful in bringing about that desired outcome. Our position on settlements remains as it has been.”

Even some of those arguing that a decision not to veto could promote the peace process say their effort is mostly symbolic and unlikely to succeed.

“I expect a straight veto, and the administration will justify it by saying this is a problem the parties themselves have to work out and that the international community can’t do it,” said Edward Walker, a former U.S. ambassador in Tel Aviv. Last week Walker signed a letter orchestrated by the New America Foundation’s Steve Clemons, along with controversial figures such as John J. Mearsheimer and Stephen Walt. “But it’s healthy to raise the issue and discuss it.”