Speaking at the World Economic Forum at Davos last month, John Kerry, the U.S. secretary of state, spoke of the need to solve the "intractable" problem of brokering peace between the Israeli and Palestinian people. Intractable is a big word. It suggests the problem is insoluble, when the reality is that it is not.

Support for a two-state solution — an independent Palestine alongside the state of Israel — is not a constant, as Peter Beinart illustrated in his book "The Crisis of Zionism." After Oslo, the high-water mark of optimism, it steadily declined through the second intifada and the conflict with Gaza. Even now, there exists an odd tension in public opinion on both sides, with a desire for the two leaderships to negotiate a settlement set against a much weaker conviction that they are capable of doing it.

None of this should be surprising. Politics, not least the politics of peace negotiations, swings constantly between optimism and pessimism. On one side is the drama of the possibility of change energized by expectation. The other is characterized by a wary stasis.