There are many flies waiting to spoil the ointment of the Middle East peace talks, not least Israel's recent announcement of a rash of settlement-building. That triggered an angry letter to Washington last week from the Palestinian leadership, though it seems Israel's serial humiliation of Mahmoud Abbas before the two sides meet was not enough to persuade him to pull out.
However, as the parties meet today for their first round of proper negotiations, it is worth highlighting one major stumbling block that has barely registered with observers: the fifth of Israel's population who are not Jews but Palestinians.
The difficulty posed to the peace process by this Palestinian minority was illustrated in the defining moment of the last notable effort to reach an agreement, initiated in Oslo two decades ago.
In 1993 Yitzhak Rabin, then prime minister, assembled a 15-person delegation for the signing ceremony with the Palestinians at the White House. The delegation was selected to suggest that all sectors of Israeli society favored peace.
When Rabin was asked why he had not included a single Palestinian, he waved aside the question: "We are going to sign a peace treaty between Jewish Israel and the PLO."
Rabin believed his own Palestinian citizens should be represented not by their government but by the adversary across the table. The mood 20 years on is unchanged. The Palestinian minority is still viewed as a fifth column, one a Jewish state would be better off without.
Significantly, it was a matter relating to Israel's Palestinian citizens that nearly scuppered the start of these talks. Israeli cabinet ministers revolted at a precondition from Abbas that the release of long-term political prisoners should include a handful of inmates from Israel's Palestinian minority.
Benjamin Netanyahu, the Israeli prime minister, won a majority in the cabinet only after agreeing to postpone freeing this group until an unspecified time.
Similarly, previous experience suggests there will be an eruption of outrage should Netanyahu's promised referendum on an agreement depend for its outcome -- given the likely split between Israeli Jews -- on the votes of Palestinian citizens. A senior minister, Silvan Shalom, has already indicated that only Israeli Jews should decide.
But Israel's Palestinian minority will be thrust into the heart of the negotiations much before that.
Last weekend Netanyahu picked at one of the Israeli right's favorite sores, denouncing reported comments from Abbas that no Israeli should be allowed to remain inside a future Palestinian state. Why, asks the right, should Israelis -- meaning the settlers -- be expelled from a Palestinian state while Israel is left with a large and growing Palestinian population inside its borders?
A possible solution promulgated by Netanyahu's ally Avigdor Lieberman would redraw the borders to expel as many Palestinian citizens as possible in exchange for the settlements. There is a practical flaw, however: a land swap would rid Israel only of those Palestinians living near the West Bank.
Netanyahu prefers another option. He has required of the Palestinian Authority that it recognise Israel as a Jewish state. This condition will take centre stage at the talks.
Leaders of the Palestinian minority in Israel are intensively lobbying the PA to reject the demand. According to a recent report by the International Crisis Group, Palestinian officials are still undecided. Some fear the PA may agree to recognition if it clears the way to an agreement.
Why does this matter to Israel? In the event there is a deal on Palestinian statehood, Israel will wake up the next morning to an intensified campaign for equal rights from the Palestinian minority. In such circumstances, Israel will not be able to plead "security" to justify continuing systematic discrimination.
The Palestinian minority's first demand for equality is not in doubt: a right of return allowing their relatives in exile to join them inside Israel similar to the current Law of Return, which allows any Jew in the world instantly to become a citizen.