President-elect Barack Obama will have to carry a heavy burden: restore confidence in global markets and manage a country amidst a recession; confront the risk of nuclear proliferation; and contain the rise of forces that are inimical to free markets, civil rights and open society. We wish him well - for it is a daunting task.

In the Middle East, too, we trust that President Obama will, like his predecessors, protect regional stability and guarantee access to energy resources for the global economy. His support for Israel should not be questioned. The two countries share interests and values much more enduring than the political differences between Republicans and Democrats.

Nevertheless, and regardless of how small and nuanced a shift in US Middle East policy might be, we hope that President Obama will recognise that some regional challenges are not easily resolved.

This applies especially to the Arab-Israeli dispute. Despite differences of emphasis and timing, US policy under five successive presidents - both Democrats and Republicans - has been driven consistently by good intentions but bad understanding. There is a difference of approach between the two sides at the heart of the Arab-Israeli conflict, which makes it intractable.

Israel, together with its Western partners, believes that compromise is the key to solving the dispute. The Palestinians, by contrast, believe that the solution only comes through justice. Compromise means, for Israel, finding the perfect point of equilibrium on the map of Arab-Israeli grievances, through a complicated but achievable balance of mutual concessions, economic incentives and security arrangements. For the Palestinians, justice means rectifying the historic wrongs their people suffered, in their own judgment, at the hands of Israel. This includes an absolute recognition of a so-called "right of return" for Palestinian refugees and their descendants to areas that today are inside Israel's borders. For Israel, this kills compromise. For Palestinians, renouncing it kills justice.