[gdpgreg]

Cause someone murdered the leading scientist in the field. Also there's concerns that it'd be too easy to turn it essentially into a very long range, highly effective weapon that could lob nuclear or conventional projectiles at countries on the other side of the planet with little to no warning.

[ben-schaaf]

We already have highly effective weapons that can lob nuclear or conventional projectiles at countries on the other side of the planet with little to no warning: ballistic missile subs.