In an effort to woo the uncommitted, pro-Palestinian advocates frequently insist that one can be pro-Palestinian without being anti-Israel. In theory, that seems self-evident. But in practice, it’s often false. Just consider the parliament of Iceland, which on Tuesday became the first Western parliament to officially call for Israel’s eradication.

I’m sure many of the parliamentarians who voted for the resolution didn’t realize that was what they were doing; they just thought they were voting to become the first Western country to recognize a State of Palestine in the 1967 lines. Indeed, the resolution even urged Israel and “Palestine” to sign a peace agreement for “mutual recognition.”

Except, it also affirmed “the rights of Palestinian refugees to return to their former homes.”

In other words, the resolution declared that it isn’t enough for the Palestinians to have one state; they ought to have two: one in the West Bank, Gaza and East Jerusalem, and another in pre-1967 Israel, which would be converted from a Jewish-majority to a Palestinian-majority state by flooding it with some five million descendants of the 1948 refugees. That, after all, is how Palestinians interpret the “right of return,” and having accepted the Palestinian position on every other issue – from where the border should lie to whether or not peace with Israel must precede statehood –there’s no reason to think the resolution didn’t intend to adopt the Palestinian position on this issue as well. Indeed, that’s the literal meaning of the phrase “return to their former homes”; diplomats seeking to square the circle of the Palestinian demand for a “right of return” and the Israeli insistence on not committing national suicide usually use some variant like “a right of return to the Palestinian state.”

And that’s the basic problem: There is no way to be both “pro-Palestinian” and “pro-Israel” as long as the Palestinians insist, as they have throughout 18 years of negotiations, that no solution to the conflict is acceptable if it doesn’t include eradicating the Jewish state via the “right of return.” There is no way to be both “pro-Palestinian” and “pro-Israel” as long as 77 percent of Palestinians think “Palestinians’ rights cannot be taken care of if Israel exists” and 66 percent of Palestinians see statehood as a mere stepping-stone to Israel’s ultimate eradication. As long as one side seeks to eradicate the other, the parties’ goals are fundamentally incompatible. And it’s only by shutting their eyes to the true nature of the Palestinians’ demands that well-meaning Westerners can delude themselves that it’s possible to avoid choosing sides.

Iceland’s decision would be bad enough even without the “right of return”; it prejudices the outcome of negotiations and approves the establishment of a Palestinian state at war with Israel. With it, however, it’s beyond the pale, and American Jews and their congressional allies must make this clear.

But it’s also time to drop the fiction that one can be “pro-Palestinian” without being “anti-Israel.” As long as the Palestinians’ list of nonnegotiable demands includes destroying the Jewish state, anyone who backs their positions is indeed anti-Israel.