Taking sides among the conflicting factions in the bewildering and dangerous Middle East undercuts the United States' potential to act as a stabilizing peacemaker. This is especially true with regard to two of the most volatile and competitive players, Iran and Saudi Arabia.
However, to the extent that we have chosen a side, we have chosen the wrong one.
As many have noted, President Donald Trump appears to have an attraction to the strong autocratic regimes that are on the rise worldwide. If you're looking for a telling global index on the state of tyranny, observe the warm, smug greeting between Saudi Crown Prince Mohammed bin Salman and Russian President Vladimir Putin at the G-20. Neither leader appears to be even slightly embarrassed by the fact that both have murdered their critics.
Uncomfortable politics at home spared us the spectacle of Trump joining in the laughing, glad-handing reunion between M.S.B. and Putin. But Trump's commitment to Saudi Arabia is clear, and one has the feeling that the attraction goes beyond oil and arms sales.
But Trump's preference for Saudi Arabia over Iran is shortsighted. His administration is unlikely to understand in a meaningful way the long-time rivalry between these antagonists, one Shia and Persian, the other Sunni and Arab. It is unlikely to take into account their deep cultural and historical differences or accurately evaluate the long-term potential for each to contribute to Middle Eastern stability.
The Kingdom of Saudi Arabia dates only to 1932, and its current prominence is an accident of geography, which located the country above extensive petroleum reserves. It's never been anything but a monarchy. The royal family maintains power by means of its vast wealth, brutal repression, torture and imprisonment without due process.
It is a country that discriminates against women and punishes its subjects with public decapitation and brutal corporal punishments of up to a thousand lashes. Occasionally Saudi subjects are stoned for adultery or suffer amputations for crimes such as theft.
And it's highly likely that M.S.B. had prominent critic Jamal Khashoggi murdered and dismembered.
By no means does Iran have clean hands in the Middle East, nor does it have a good record on human rights. Since 1979, it's been ruled by a repressive theocracy whose meddlesome ways have fostered instability and suffering.
On the other hand, Iranians look back with pride on two past millennia that include the great Persian empires of Cyrus and Xerxes. And modern Iranian history reflects serious inclinations toward democracy that date back at least to its revolution in 1906, which replaced a dynasty with a constitution and parliament.
Unfortunately democracy in Iran was thwarted by petroleum-hungry powers, first the British in 1921 and then the United States in 1953. For most of the 20th century Iran was ruled by an autocratic shah maintained by the U.S. as a bulwark against communism. The shah's repressive, corrupt regime made the 1979 revolution almost inevitable. But the 40 years since are only a brief episode in Iran's long history.
Women have more freedom in Iran, and the results of recent elections, as well as the extensive protests of 2009, indicate a prominent attraction among Iranians for moderation and openness.
Which of these two countries, Iran or Saudi Arabia, is more likely to respond to deft diplomacy?
A United States commitment to either side in the growing competition between Saudi Arabia and Iran for hegemony in the Middle East threatens the helpful balance of power between these two rivals and makes armed conflict more likely.
But if we're going to choose sides, let's not choose the wrong one.