This relationship...

...clearly has several levels of trust throughout the decades.  Forget the pollyanic notions of global unity or similar theories of peace based on commercial ties or the like.  It all reduces to military capability...and the more U.S. military assets one purchases, the more likely continued "support" is forthcoming.

WASHINGTON — To wage war in Yemen, Saudi Arabia is using F-15 fighter jets bought fromBoeing. Pilots from the United Arab Emirates are flying Lockheed Martin’s F-16 to bomb both Yemen and Syria. Soon, the Emirates are expected to complete a deal with General Atomics for a fleet of Predator drones to run spying missions in their neighborhood.

As the Middle East descends into proxy wars, sectarian conflicts and battles against terrorist networks, countries in the region that have stockpiled American military hardware are now actually using it and wanting more. The result is a boom for American defense contractors looking for foreign business in an era of shrinking Pentagon budgets — but also the prospect of a dangerous new arms race in a region where the map of alliances has been sharply redrawn.