The tender battle between Boeing and Airbus has completed its third round (Boeing won 1st round, battle was restarted, Airbus won 2nd round, battle was restarted, Boeing won 3rd round a few days ago).
This reminds me of the true "arms deal of the (20th) century"*; the C-135 "Stratolifter" and its key role as foundation for the airliner business success of Boeing. Hundreds of C-135 aircraft (and variants) were sold to the USAF.
This aircraft (internally known as Boeing 717) also became the Boeing 707 a year later (both originated from the "Dash 80"). The Boeing 707 was the great breakthrough for turbojet-driven passenger air traffic after the Comet had experienced pressurized cabin problems. The USAF support for Boeing in form of huge C-135 sales was likely the key difference between Boeing and its competitors.
The Dash80/C-135/Boeing 707 also defined the dominant aircraft layout for airliners: swept wings, engine nacelles suspended blow the wings, normal swept tail and tubular pressurized fuselage. I have a book on aviation from the late 50's and I can tell you that people didn't consider this layout as self-evident then, while they do so today.
The new tanker competition won't be nearly as important as the choice of the C-135, not the least because it's backwards. This time the military aircraft will be based on a civilian aircraft.
This seems to be true for many military orders nowadays.
*: "Arms deal of the century" is conventionally known as description for the F-16 tender, but that decision was much less important than the choice of the C-135.