I came to the conclusion that McNamara was planning to take over Vegas and the securitrons. To support my idea, I have Head Scribe Taggard, the screen in McNamara chamber and Yes Man and Mr. House attidute toward the BoS.

Let's start with Taggard. He is a programmer who shoudn't be Head Scribe, according to Senior Scribe Schuler. When she complained to McNamara, he didn't say she was wrong, he said that Taggart is essential to the cause. Schuler herself thinks that the simulations aren't that essential, so I think we can assume that he is working on somehting big related to computers. Perhaps he's trying to find a way to take control of the security army? Maybe the BoS found that virus when thery were looking for some hacking system?

The screen on McNamara shows few strategic locations: Black Mountain (long range communications, but can it be used to trasmitt datas to Lucky 38?), Hoover Dam, Camp McCarran (the only RNC camp that is shown on that map), the Lucky 38 and the Repcon site (don't know why it's there).

So IMHO McNamara's plan was to wait for the NCR to focus on the dam, invade Camp McCarran when it was half empty, use the monorail to assault the Strip in forces, occupy the Lucky 38 and take over Vegas and the securitrons. The paladins cannot go through Freeside: they would be easly spotted and Mr. House wouldn't have problem ralling all securitrons to the gate. McNamara plan relies on the element of surprise, his troops have to go in the strip with quick violence. Hard to blame him, he has few tens of paladins left.

Now I think that both Yes Man and Mr. House smell out the plot. Yes Man is highly confident in the power of securitrons ("who cares about other people support? You have an army of securitrons!), yet to him the BoS is the greatest threat to the courier's plan. I doubt it fears a direct confrontation with few tens of paladins, it is scared because the BoS can override its program. It is a powerful computer, it knew what path the courier would have crossed despite Mr. House attempts of misdirection, and he can decrypt Mr. House datas. It wouldn't be strange to me if it calculated correctly the danger the BoS can pose, even if it hasn't way to know they are planning something.

Mr. House has no doubt about the plan. He wants the BoS dead, at all costs. It would be in his interests to have an other faction challenging the NCR once the legion is gone. But he doesn't want the BoS around, even as allies. He has also taken precautions trying to anticipate McNamara. I was amongst those who thought that Mr. House filled Vault 21 with cement out of paranoia, more than actual security. But if I knew some force could attack the Strip by the monorail, I would destroy a place were said army can retreat and pose a lasting threat too (I have finally understood your point, Martyr). Then there is this move of pure genius: he knows that his army is too small to allow him to disperse units, and he knows the monorail it's his weakest spot. So what does he do? He prompts the NCR to take over McCarran, so when they think they won a good logistic base bargaining with House, they are unknowingly guarding his weakest spot.

Now, does that mean that independence is BoS victory? Afterall, there are few reasons to prefer anarchy to House, beside the fact that you can spare the BoS. And if indie is canon? Would the BoS have a state?

Also, sorry if somebody has already posted this, and I bet somebody already did, the game is years old. But I'm bored waiting for FO4.