Send them with a pack of stamped addressed bodybags?

Kosiak draws a distinction between militarisation and weaponisation; in this sense isn't a more valid comparison to be drawn not with the dreadnought races of the early 20th Century, but rather the early militarisation of the air. Early aircraft were primarily initially used by the military as an intelligence gathering tool also, and initial attempts to give them combat capability were...well...."Just fly above the other chap and drop this hand grenade on him, will you?"... That said, we saw rapid progress in the aerial theatre.

is that Games Workshop owns the copyright on Space Marines ;)

You don't need nukes for your Death Star fleet. Dropping big enough rocks onto your target is more than enough to stop any problem - see Footfall by Larry Niven & Jerry Pournelle.

Even a 'Project Thor' would be enough of a deterrent to most operations and have maximum 'Shock & Awe' value...

I remember the good old times when the "UN Space Navy" was meant to defend Earth from Aliens, and it didn't shy away from hiring disturbingly cute female officers either:

http://en.wikipedia.org/wiki/U.N._Spacy

"But after the Cold War against the UN was won by General Bolton, the US assumed in-depth defense of Earth against the Sandnigra Empire and assorted Yellow Forces."

or before Footfall, Heinlein's "The Moon is a Harsh Mistress".

...some of the fastest development of technology could arguably be attributed to the Cold War arms race. A space weapon cold war would undoubtedly spur on the same rapid development, in a way that civilian spaceflight could never hope to.

"How Ironic that the greatest forge of civilisation is war."

Bring on the space race, i say!

http://en.wikipedia.org/wiki/Kinetic_bombardment

Deorbiting tungsten rods onto targets at 5km/s? I'll take one of those, please.