Gunboat diplomacy was the essence of military power projection for centuries. Want to coerce a country? Sail a aircraft carrier battle group into their national waters.
However, carrier battlegroups are hideously expensive, increasingly vulnerable to low cost attack, and less lethal than they appear (most of the weapons systems are used for self-defense).
What are nation-states replacing them with? Drones. You can already see it in action across the world as drone staging areas are replacing traditional military bases/entanglements. Further, drones already account for the vast majority of people killed by US forces.
Of course, the reason for this is clear. Drones are relatively cheap, don't require many people to deploy/operate, don't put personnel directly at risk, can be easily outsourced, can be micromanaged from Washington, and are very effective at blowing things up.
The final benefit of Drone Diplomacy: drones make it possible to apply coercion at the individual or small group level in a way that a blunt instrument like a carrier battle group can't.
What does this mean?
It allows truly scalable global coercion: the automation of comply or die.
Call up the target on his/her personal cell (it could even be automated as a robo-call to get real scalability -- wouldn't that suck, to get killed completely through bot based automation).
Ask the person on the other end to do something or to stop doing something.
If they don't do what you ask, they die soon therafter due to drone strike (unless they go into deep hiding and disconnect from the global system).
With drone costs plummeting, we could see this drop to something less than <$1000 a strike in the next half dozen years (particularly if kamikazee drones, like Switchblade, are used to reduce explosive payload requirements).
What can we look forward to?
The mid term future of a national security apparatus in secular ($$) decline?
Drones, drones, and more drones. Shrink the headcount. Cut training. Put manned weapons systems in life support mode. Cut mx.
All the money is on cyber intel (to generate targets based on "signatures") and drones to kill them. When domestic unrest occurs in the US due to economic decline, these systems will be ready for domestic application.