Binks (firstname.lastname@example.org) writes:
Just had an interesting thought, why do the Covenant 'glass' planets? It could be a sound military tactic for them to develop in response to the Spartan II's however it's clearly not from the incident on Harvest in which the planet was destroyed by the first Covenant attack and a "thin gray sunlight reflect[ing] off a glassy crust" was seen, obviously showing that the planet had been glassed long before the Covenant knew of humanities ability at ground combat and the Spartans. I've come up with 3 possible reasons for the development and deployment of this tactic by the Covenant:
1. The Covenant hate humanity so much that they care more about wiping us out that securing new worlds. This is probably the least likely based on the available evidence, despite how possible it may seem. Firstly it would be Horrible tactics, Scorched Earth is a tactic used when retreating from a superior enemy, not destroying an inferior one. Why in the world would you destroy perfectly habitable worlds like that when you could bombard select sites then invade and gain a new planet? We have direct evidence of Covenant forces invading a planet which they felt no qualms about glassing in FoR when Master Chief leads the Spartans in a plan to hurt a large ground force, and is subsequently pulled off the planet that is glassed. I don't think that the Covenant would glass a world with any significance Forerunner artifacts, even if their ground forces evacuated many of the relics, and so I think it's safe to assume that glassing wasn't the Covenant's only policy for dealing with human planets.
2. Humanity was an unknown enemy, in the first engagement the Covenant likely had few troops in their relatively small ship and may have brought no reinforcements for some reason and so glassing Harvest was the best way to deal with the planet and send a message to the humans, sort of a "Your space vessels are weak, it doesn't matter what unknown capabilities you may have on the ground, we can crush you as easily and with as few vessels as this planet was crushed" or something. This would require that the Covenant had developed and implemented glassing before, perhaps as a scare tactic to get other races to join them (which leads to my theory that the Human-Covenant war is nothing more than a misunderstanding, that the Covenant expected Humanity to immediately surrender to them and become another of the Covenant races, perhaps like other races had, and that humanities response, fighting and winning, was heresy to the Covenant, but that's another topic for another time)
3. Glassing a planet was a common tactic for the Covenant because, dun dun dun dun, they had a long history with the Flood. I mean, what better way (besides cleansing the galaxy of life) of dealing with an adaptive absorbing enemy than the wipe them out from orbit by destroying the entire biosphere? ("[Glass] it from orbit, it's the only way to be sure") Glassing seems like a perfect weapon against any Flood incursions, oh they're on this planet? Oh well, goodbye planet. Inefficient? Merciless? Terrible? Effective? All true. Perhaps then the Covenant see humanity as nothing more than another enemy like the Flood, a "vermin" to be wiped out. Since they know they can't cleanse our worlds of all of us (Reach's remaining Spartans in First Strike, the civilians on Sigma Oct. in FoR etc.) they just glass the planet from orbit to make sure none survive, none are "left behind" if you will. (Note that this is slightly different from the hate theory in #1. Treating humanity as a Flood like virus doesn't imply hate, just that they're willing to sacrifice a planet to destroy us)
Or perhaps - in regards to Number 3 - their military methods are based on the tactics the Forerunner used to fight the Flood. The Covenant can scavenge anything.