Doug Freyburger wrote:
I recall Saddam Hussein at one point before the Iraq wars had a project
going that was called the "world gun". Fire from a long enough barrel
and use a projectile that can adjust its orbit near the apogee of its
original orbit and you can shot in one direction and the projectile can
do a couple of orbits and hit anywhere on the planet. Accuracy would
suck for the first several hundred shots and by then commandos will have
shown up and taken the facility out.

Besides being a sitting duck target for an air strike, it was also too
big to be slewed to aim at different targets:
http://www.astronautix.com/lvfam/gunnched.htm
Although a lot of people assume Israel's Mossad assassinated him over
the cannon, it was more likely they offed him over his work on IRBMs
using Scud technology: http://www.thespacereview.com/article/1498/1

Pat