Many of the 20th century’s crises were touched off or worsened by these kinds of great-power/client-state dynamics — between Russia and Serbia in 1914; between Stalin and Kim Il Sung in 1950 and Khrushchev and Castro in 1962; and between the U.S. and various South Vietnamese governments across our long Indochina debacle.

The problem is still with us today. The brush-fire war between Russia and Georgia in 2008, for instance, probably wouldn’t have happened if America’s patronage hadn’t made our Georgian allies overestimate their ability to engage in brinkmanship with Vladimir Putin. (Happily, John McCain’s half-cocked declaration that “we are all Georgians” was the closest we came to starting World War III on Tbilisi’s behalf.) And the 2003 Iraq invasion was shaped, in part, by perverse patron-client dynamics as well: it was both a continuation of Gulf War I, which was fought on behalf of our gulf-state clients, and an attempt to effectively replace those (highly problematic) allies with what various Bush-administration optimists hoped would be a new and very grateful client in the heart of the Middle East…

Right now, the Obama administration is trapped by its client state the way that great-power patrons often are. Because our aid to Egypt is our most obvious leverage over its military, and because we can really only pull that lever once, Washington is afraid to follow through and do it.

But leverage can be lost through inaction as well.