The bombing in Dhahran, Saudi Arabia, which took the lives of 19 Americans, inevitably raises questions about the close relationship between the Saudi regime and the United States.
Is the relationship too mercenary, with the Saudi royal family buying protection and the US gaining assured access to the world's largest pool of oil? Does it ignore the tensions in Saudi society - tensions heightened by the presence of US forces? Is the relationship inherently at odds with Saudi Arabia's deeply Islamic culture?
Such questions have become more urgent in the years since the Gulf war. The Americans who came first to beat back Iraq have stayed on as an insurance policy, and to carry out continuing surveillance operations against Saddam Hussein. They also became a red flag for dissidents and radicals who see the House of Saud as a corrupt institution kowtowing to the West.
The recent bombing in Dhahran and an earlier one last November in Riyadh showed the explosiveness of such feelings - as well as the ability of those who hold them to muster significant ordinance and technical know-how. There may be involvement by antagonists in neighboring lands - Iraq, Iran, Sudan, Yemen. But the fundamental problems are internal, ranging from an economic downturn and growing unemployment since the war (which burdened Riyadh with massive bills) to persistent criticism of the government and of its US ties from younger elements of the clergy.
The imminent changing of the guard within the Saudi regime, as an ailing King Fahd withdraws from public life, adds another note of uncertainty.
Should the US take these cues and lower its profile, if not actually withdraw? In fact, Washington has been acutely aware of the problems that could arise from too pronounced a presence in the birthplace of Islam and has tried to keep a low profile. But thousands of service personnel can't be made invisible. They are there because the US, alone, is ready and able to maintain peace in the neighborhood. And most Saudis, for all their economic and political troubles of the moment, appreciate that.
And the oil? It remains the core of American interest in the region. Prudence, conservation, and new technology (both electric car engines and new ways of extracting oil from domestic fields) may yet reduce dependence on Gulf oil, but that won't happen soon.
Meanwhile, the US should sustain its presence, adjusted to need, so long as the government in Riyadh asks for it. It may never be the most comfortable of relationships, but it remains a crucial one.