But, Arens added, the Palestinians in that territory should be made full citizens of Israel. This statement is revolutionary: If it were really possible to engineer a one-state solution that gave full rights to Palestinians, it would be unnecessary to continue negotiations for a Palestinian state.
Yet most Israelis (and Palestinians) do not think a one-state solution is workable.
Those Israeli leaders who have sought a two-state solution have done so out of fear that Jews will soon be outnumbered by Arabs in Greater Israel, and that the Arabs would then seek control.
The CIA Factbook says about 2.5 million Palestinians live in the West Bank, and 1.6 million in Gaza, while 20 percent of Israel's 7.3 million citizens are Arabs. Given that the Palestinian birthrate, though dropping, is higher than the Israeli birthrate, the trend appears clear.
That will leave Israel with two daunting choices. The first is to continue controlling an Arab majority, most of which has no civic rights. This would destroy Israeli democracy and brand Israel as an apartheid state.
The second choice - opposed by most Israelis - is to grant citizenship to Palestinians in the West Bank and Gaza. However, the idea that Israelis, West Bankers, and Gazans can live together in one state ignores the realities of the region. The Middle East is dominated by communal politics, in which trust of the other community is absent: Think of the bloody struggles between Sunnis and Shiites in Iraq and Lebanon.
Two communities that each want sovereign control and are of roughly equal size, such as Israeli Jews and Palestinian Arabs, are bound to battle for power. That is a formula for constant civil war.
So why does Arens advocate a "one-state solution"? Perhaps because he, like numerous Israelis and Palestinians, is casting about for what to do when the peace process ends.
Many Israelis across the political spectrum believe the demise of the two-state option will pose a great danger to their country. The current calm on the West Bank, and the enforced calm in Gaza, would be likely to give way to renewed violence and chaos.
Arens says the status quo can last for a long time, but he's still searching for better options. Yet such options are almost impossible to find.
In the 1980s, Israelis hoped that Jordan would take responsibility for the West Bank Palestinian population, and some Israelis now wish Egypt would take back Gaza. But Jordan and Egypt have their own problems and are unwilling to oblige.
This brings us back to Arens' version of the "one-state option." Does it offer an alternative that could work? Afraid not.
For one thing, Arens omits Gaza. "Gaza is a basket case," he said, "and is something Israel could not absorb under the best of circumstances." He's correct, but this glosses over what to do with 1.6 million Palestinians in a tiny territory whose borders are still controlled by Israel.
For another thing, Arens relies on contested statistics that downsize the West Bank population to 1.5 million.
And a third caveat, of critical importance: Arens believes West Bankers could not be granted citizenship "until after the integration of Israel's Arab citizens, a situation we haven't arrived at yet." Indeed, tension between Israel's Jewish and Arab citizens has been growing lately, in the wake of discriminatory Israeli legislation.
If Israel is having increasing problems integrating its own Palestinian citizens, how could it handle 1.5 million, let alone 2.5 million, more?
So why do I raise Arens' proposal? Because if the two-state option collapses, a one-state option will be all that remains. This grim reality is nearly upon us. If Israeli and Palestinian leaders, along with the White House, can't revive talks about two states for two peoples, they'll have to confront the impossible option: one country containing two peoples in a state of perpetual war.
Trudy Rubin can be reached at firstname.lastname@example.org.