For decades now, American liberals who support the idea of Israel as a Jewish state have been torn up over Israel's behavior. Israel's politics have veered increasingly hard right. It has caused the United States no end of trouble. And it refuses to give up its occupation of the West Bank and Gaza — the latter of which has become a hellish open-air prison camp under a strangling Israeli blockade.

This prompted The New York Times' Michelle Goldberg to write that "liberal Zionism" — or the idea of an Israel that is both Jewish and democratic — is basically dead. She is surely right. But it's also time to consider the idea that Zionism itself was a flawed idea from the start.

As Tony Judt wrote over a decade ago, the idea of a particularly Jewish homeland is rooted in nationalist ideology from the late 19th and early 20th century. This ideology that has been progressively discredited since that time. The modern nation-state often retains some nationalist flavor, but the standard basis of nations today today is citizenship defined through membership in national institutions, not ethnicity, religion, or race. "Israel, in short, is an anachronism," he put it.

Of course, Israel is a special case. Jews were the victims of the worst crime in history. It is completely understandable to conclude that they need a place of refuge in case some new power succumbs to the mind disease of anti-Semitism and tries to exterminate the Jews again.

But the concept of a refuge for Jews is logically distinct from a Jewish ethno-state. This distinction is critical.

The major problem with Israel is the occupation of the West Bank and Gaza. It is a tyrannical domination of a subject population, the source of endless conflict, and arguably the greatest long-term threat to Israel's security (despite its military superiority). If the problem can't be resolved, the international animus it inspires will continue to fuel the pressure for boycotts and sanctions, and will someday probably lose Israel free access to America's United Nations Security Council veto.

In all the territory controlled by Israel, there are over 6.2 million Palestinian Arabs, and about 6.5 million Jews. The Israeli birthrate is high, but the Palestinian birthrate is higher. Someday soon, Arabs will outnumber Jews in Israeli-controlled territory.

This leads directly to the dilemma of liberal Zionists: If Israel wants to remain democratic, it can either divest itself of the occupied territories, and thus retain its Jewish majority, or it can become one single state that is half Jewish and half Arab. The former is all but impossible to imagine, given the total collapse of the peace process. The latter would mean abandoning the idea of a particularly Jewish nation.

If Israel continues the occupation without giving Palestinians full citizenship, it will have abandoned democracy. This seems the most likely outcome. Indeed, by most definitions of the term Israel has been a de facto apartheid state for decades now — in the 2015 election campaign, Benjamin Netanyahu overtly promised that he would prevent the formation of a Palestinian state while he was prime minister. The demographic balance tipping to an Israeli minority would merely check one of the last boxes on the apartheid checklist.

We can draw a straight line from basic Zionist principles to this dilemma. If you are justified in seizing some land in one's ancestral homeland — and make no mistake, that is what happened when Israel was created — why not take more? The occupation has been fueled by many things, but perhaps the most important one is endlessly encroaching settlements on the West Bank motivated by religious-nationalist aims. Indeed, many of the settlers currently living there are religious fanatics who would resist resettlement by force.

The path to maintaining a Jewish majority state in this situation is clear enough: Just trim the voting rights of non-Jews, or retain control over territory for "security reasons" while denying full citizenship to residents of that territory.

Fifty years after the 1967 war that established the occupation, arguments that it's all the fault of Palestinians or simply a security necessity ring increasingly hollow. If Israel wants to do more than preserve the wretched status quo, all while running an increasing risk of being treated as an international pariah state, it should re-examine its most basic assumptions.