The idea of the one-state solution keeps popping up, particularly when the two-state solution is undergoing difficulties. Maybe this is because people in the region are unable to imagine anything other than one- or two-state solutions.

Recently, and in view of the serious difficulties facing the peace process as well as the evident drift toward radicalization and the political right in both Israel and Palestine, we have again begun hearing the idea of a one-state solution.

In Ramallah and other main cities of the West Bank, slogans on billboards have recently sprung up in many places calling for a solution to the Palestinian-Israeli conflict based on the equality of all people between the river and the sea: one secular, democratic state on the basis of one-man, one-vote.

Public opinion polls on the Palestinian side show that those supporting a one-state solution are still a minority. However, the number of supporters of the idea has been growing slowly but steadily.

During the same period there has been a faint echo of this line on the Israeli side. This has not come, surprisingly, from the Israeli left as one might have expected, but rather from the far right, including settlers. Those proposals should not be confused with the equal-rights-for-all-people that Palestinians suggest, but are rather an apparent attempt at ensuring a Jewish presence in all historic Palestine.

The rightists behind these proposals are opposed to a two-state solution, which will deny them the ability to live in the part of historic Palestine that constitute a Palestinian state.

The problem with the one-state solution is that it appears less plausible than the two-state solution. This is, first, because the vast majority of Israelis, and certainly Israeli officialdom, is unwilling to even consider the option. Most Israelis seek a "purely Jewish state". A one-state solution will leave that state even less "pure" than what Israel would be under a two-state solution.

Second, most Palestinians are not willing to invest in the one-state solution for practical reasons. They don't see a chance for this option and are more confident in chances of a two-state solution. Some Palestinians even go further and argue that to even raise the idea of a one-state solution is harmful, because it might undermine the possibility of a two-state solution.

Third, there is an accumulated body of international resolutions and international consensus that supports the two-state solution.

Having said that, it is conceivable to imagine that the more time passes without a two-state solution on the 1967 borders, the more likely we are to see the emergence of a single entity between river and sea, comprising one state, Israel, alongside an apartheid reality in the rest of historical Palestine, where two peoples sharing the same land live under two completely different sets of laws.

The changes Israel is undertaking in occupied East Jerusalem, including settlement expansion and infrastructure construction, are eliminating the practical possibility of turning occupied East Jerusalem into the capital of a Palestinian state. This will certainly undermine chances of an independent Palestinian state on the borders of 1967 and, consequently, eliminate the two-state solution.

This will leave us with the reality of the one-state-plus-apartheid entity, which will eventually lead to one state. The problem here is that the time this takes will be neither short nor quiet. Rather it will spark renewed tension and violence, more extremism and hatred, and the conflict will continue to be a cause of instability in the region at large.

The international community, which adopted the two-state solution and convinced the Palestinians that this option is, for pragmatic reasons, the only possible one, now has to take a more active role to realize this vision.

That has to happen soon, before it is too late. Leaving the future of the conflict up to bilateral relations between the Israelis and Palestinians has proven futile because of the vast imbalance of power between the two.

The combination of the upcoming American-led direct talks and the impressive performance of the Palestinian government on the ground in preparing Palestinians for statehood is an historic opportunity that needs to be used seriously by the international community.