When you fight at Hoover Dam under Wild Card, when you first get to the Dam Yes Man presents you with the choice of either destroying the Dam's generators or redirecting it to power up the extended Securitron army underneath the Fort. This is an in-game choice.
Personally I like this route for Wild Card better because the other one is just "Mr. House,except it's me."
Oooooh that's interesting. I don't really notice there's such choice at all. Really accentuate the fact that the route is called 'Wild Card'; even Yes Man might get surprised at the Courier's choice.
However, I can't help but think it's nothing more than an option for edgelord Courier who just want to do it for shits and giggles. Like I said, the only reason the NCR will ever trade with Vegas-Mojave is because of the electricity and clean water produced by the Dam, with the added benefits of vast farmlands thanks to mostly clean soil as evidenced by NCR Sharecropper Farm. And it's really important for the NCR to trade with Vegas-Mojave to ensure civilization advancing in the region. So, what would happen if the Dam is to be destroyed? Well, not only the entire region will lose its major value (mainly electricity, clean water can just be gathered from Lake Mead-Colorado River), losing access to all those Securitrons means the Courier pretty much condemned the Mojave with a vulnerability that will be exploited either by the NCR or the Legion. Mostly NCR, I think, to settle the score of being double crossed.
I just find "Mr. House but me" to be a boring power fantasy. And I think Ulysses is right about House in saying that those walls of his will keep expanding until the Mojave is Vegas. You already get implications of that in the endings where he sends Securitrons to patrol Goodsprings and Primm.
The only reason why Ulysses will see Mojave becoming Vegas should the Courier let House takes over is because he didn't know of House's plan for Vegas, Mojave, and humanity in the future.
Now, House only sends Victor to Goodsprings. That's one (1) Securitron, of which the locals are already familiar with. Meanwhile, House will only sends a patrol to Primm
if you let them get annexed by the NCR. Assign Meyers or Primm Slim as the law and order for Primm, and House will leave them alone.
Pretty sure losing the dam battle breaks the Legion's stride regardless of if the dam's power is inoperable. But whatever, regardless the ending slides confirm that the Legion and NCR never take the Mojave.
Which confuses me: why the Dam rendered inoperable, and in turn the Securitrons not getting powered up, changes nothing in the ending slides? Both the NCR and the Legion will have good reasons to take the Mojave despite of losing the Second Battle. The NCR will definitely want to hold the Courier responsible for double crossing them, and the Legion will definitely want to try again;
especially there's no army of Securitrons to keep them at bay.
It'll have an effect in NCR, sure, but it'll all get pinned on Kimball and Oliver (assuming they're alive) and probably teach the NCR a very good lesson in why constant expansion isn't a winning strategy.
But you can already do this without having to sabotage the generators. Just divert the power to the Securitrons, have them rise from beneath the Fort, and kick not only the Legion's, but also the NCR's ass. This is already part of House's plans since before the Courier's rising from the grave, and it's not hard to think this plan is taken over by Yes Man once he's installed in Lucky 38's mainframe.
As for the citizens of New Vegas, I highly doubt it will make a difference. As I said already, there's content that explains that the El Dorado substation upgrade secures electricity for New Vegas so that it's resource independent from the Dam. As for trade and the like, the variation for whether you destroy the dam or not doesn't actually change any of the slides so for towns like Goodsprings (and Primm under Primm Slimm), independence allows them to prosper and thrive.
Which is a bad thing from the developers side: why would they implement an option for players to choose, only for it to not have any meaningful effect at all? Either it's a cut content, or they didn't think this through.
Even without the dam's electricity Vegas itself has its gambling allure, and the Mojave is still a major part of the Long 15 trade route into Utah and beyond (which, if you got the Honest Hearts good ending Happy Trails opens up again) and Old World Blues outright states that the Courier uses the Big MT tech to make the Mojave a better place.
You need to remember that the very reason the NCR even wants to be in the Mojave is because of the Dam. The electricity is vital to distribute energy across NCR's vast and rapidly growing territory. Destroying the Dam means you cut off that energy supply, pissing off not only the goverment but ALSO the citizens. The bulk of Vegas's customer comes from the NCR, so if they know that their energy supply is turned off simply because an asshat thinks he can, then they won't be coming to hand caps to your hands. Or they might get busy with trying to establish power supply again for their homes. Or better yet: the government can use this situation as a propaganda to drive their citizens to boycott the Mojave.
It's even more baffling how destroying the Dam's generator doesn't change anything in the ending slides, now that I think about it. The very root of this conflict is the Dam, so it being operational or not should change something significantly.
