What happends if you help the other guy who wants to be an elder leader?

You won't be able to ally with NCR if you change elders.

Thanks.

Change the Elder? I didn't know he still wore diapers. :rofl:

You also have to do a different quest if you want to join the Brotherhood. Hardin (I think that's his name) makes you wipe out the Van Graffs, since he doesn't want energy weapons being sold on the general market.