If the Trump Administration is even remotely serious about its efforts to reach any substantive agreement between Israel and the Palestinian Authority, let alone a final or “ultimate” deal, it will eventually have to cease evading the question of territorial parameters. In the case of the Israeli-Palestinian conflict, there is a widely held consensus among international policymakers that a two-state solution modified by land-swaps along the pre-1967 lines is the endgame of any serious long-term negotiating process.

At different points in the past, the Israeli government and the PA have more or less acknowledged this truth. There is nothing particularly sacred about those lines, but they carry historical and legal legitimacy, and also leave room for sufficient compromises to guarantee Israel’s security.

This rather conventional solution, despite years of attacks from activists on the left and right, not to mention serious setbacks on the ground, has stood the test of time. The two-state solution is still both the ideal and pragmatic solution to the conflict. The alternatives are untenable to various degrees.

The one-state solution proposed by some Israelis such as Tzipi Hotovely and Naftali Bennett (and Danny Danon and Dani Dayan before they took on diplomatic roles) would not be a solution in that the conflict would not even be theoretically settled: it would essentially serve as a statement of “Israeli victory.” This concept, to be blunt, is delusional and destructive. The Palestinians have been on the losing side of the conflict every day for much of the last century since the Balfour Declaration was issued and have not shown signs of giving up. It would be an unacknowledged victory, which isn’t much of a victory at all, and indeed this is more or less what Israel already has: hundreds of thousands of settlers on territory the Palestinians insist is occupied, but who have no power to change the status quo on their own. Ironically, annexation or further settlement expansion and integration would provide the opportunity for Palestinian civil disobedience to play a disruptive role that could lead to a victory of their own.

The one-state solution proposed by some Palestinians and their international supporters would amount to such a Palestinian victory in the conflict. Just like the one-state solution embraced by the Israeli right, this would perpetuate and not settle the conflict. Supporters of this one-state model often take umbrage at this comparison, asserting that such a state would be a democratic one. Perhaps, but no conflict resolution theory I know of claims that combining the populations of two warring nations and allowing the majority to determine everyone’s fate holds considerable promise. Even if one believes Zionism lacks moral legitimacy, there should be no doubt that the overwhelming majority of Israelis and Israeli Jews, including nominally anti-Zionist Haredim, favor the model of a Jewish state.

Proposals for an Israeli-Palestinian confederation are interesting but even more politically unviable than the two-state solution at the moment. It would require more extensive and continuous cooperation between Israelis and Palestinians; indeed, it would require Israelis to share sovereignty with Palestinians, and vice versa. Both sides would have to be willing to accept a clearly inferior version of statehood. Thus, for the moment, confederation remains a proposal without much of a constituency outside think tanks, newspaper editorials, and academia.

Once we arrive at accepting the two-state solution, several thorny issues remain on territory alone (the rights of Palestinian refugees and the status of holy sites represent large obstacles on their own). The settlement project may be regrettable, but much of it will be difficult to dismantle even if Israel had a government willing to do so. Israel has invested too much in the settlement blocs, parts of which also provide Israel with a needed security buffer. No one should expect Palestinians to be sympathetic, but they have shown willingness to discuss fair land swaps in the past.

If Israel is to have recognized sovereignty in some or all the settlement blocs, such recognition will be a Palestinian concession to Israel, not a Palestinian concession to reality, as some would suggest. Land swaps are the mechanism through which a compromise can be made, but it will only have support among Palestinians if the basis for compromise is one they recognize as legitimate. The most moderate Palestinian will not sit down at the negotiating table if he believes he may be confronted with a choice between a “state-minus” or a continuance of the status quo.

The challenge facing the Trump administration, and one reason why now is a particularly inopportune time to hold talks, is that the Palestinians are not ready to make concessions and Israel is led by a government deeply reluctant to negotiate on terms that have a chance of success. It is this conundrum that motivates support for alternatives to two-states on both sides. It’s difficult to mediate talks if neither side agrees about what is, in fact, being negotiated.

But if now is not the time for final status talks, it is never too early to set broad U.S. policy in anticipation of years of stalemate. If the administration wants to play a constructive role, it should make clear that it expects negotiations, whenever they do take place, to be based on the pre-1967 lines. It should also declare that Israel will not be expected to withdraw from all post-1967 territories, a fact which the Arab League effectively recognized in 2013.

To read more about proposals for U.S. foreign policy toward the two-state solution, check out Israel Policy Forum’s 50 Steps Before The Deal initiative, Step 4: Commit to a Two-State Solution.