President Obama spoke to AIPAC today and addressed the controversy his Thursday speech had caused.

He met two criticisms by backing down. On Thursday he had not mentioned the "Quartet Principles." Today he did, saying that Hamas must "accept the basic responsibilities of peace: recognizing Israel’s right to exist, rejecting violence, and adhering to all existing agreements."

He also responded to the criticisms of his call for negotiations based on the "1967 lines with mutually agreed swaps." Today the president said that:

"By definition, it means that the parties themselves – Israelis and Palestinians – will negotiate a border that is different than the one that existed on June 4, 1967. It is a well known formula to all who have worked on this issue for a generation. It allows the parties themselves to account for the changes that have taken place over the last forty-four years, including the new demographic realities on the ground and the needs of both sides."

Here the president was admitting error while claiming he had not made one. The error on Thursday was not saying, as he did today, that any agreed border would be different from the 1967 line. But the president failed again to recognize that the 1967 line was actually the 1949 armistice line, and that a return to it should not merely reflect "changes that have taken place over the last forty-four years, including the new demographic realities on the ground." In fact those lines would need to change even if not one settlement had ever been built. The changes must reflect Israel’s need for secure and defensible borders, which has long been the American position. Moreover the changes need to reflect that the 1949 lines were the product of aggressive war and were unjust: for example, the Western Wall of the ancient Temple was in Jordanian-occupied Jerusalem prior to the 1967 war, and is now--and obviously must remain--in Israel.

The president also failed to resolve one logical contradiction in his policy--one with considerable significance--perhaps because it is impossible to do so.

The contradiction is visible clearly in these lines he delivered: "we know that peace demands a partner – which is why I said that Israel cannot be expected to negotiate with Palestinians who do not recognize its right to exist, and we will hold the Palestinians accountable for their actions and their rhetoric.But the march to isolate Israel internationally – and the impulse of the Palestinians to abandon negotiations – will continue to gain momentum in the absence of a credible peace process and alternative."

So Israel should and must negotiate, but Israel cannot be expected to negotiate. If Mr. Obama wonders about criticism--and he complained about it at AIPAC--he should ponder those lines in his own speech. He said today that "If there’s a controversy, then, it’s not based in substance. What I did on Thursday was to say publicly what has long been acknowledged privately." Perhaps. It does seem that Israel is being pressured to negotiate even by those who "acknowledge privately" that it has no negotiating partner. Mr. Obama is in a separate category: he is pressuring Israel to negotiate even as he acknowledges publicly that it has no negotiating partner.