[qppo]

I think it was Kissinger that said (paraphrasing) war is a tool to achieve political objectives. The necessity, scale and manner of violence depends on what those objectives are and feasibility of success.

The kind of political dilemma that would be solved by a mecha duel would probably not be the same one that requires invasion and enslavement in death mines.

[Someone]

Kissinger may have said it, but it dates back to, at least, Carl von Clausewitz. https://de.m.wikipedia.org/wiki/Carl_von_Clausewitz:

“Der Krieg ist eine bloße Fortsetzung der Politik mit anderen Mitteln.”

(“War is the mere continuation of politics with other means”)