I've been playing on the NCR side, and am a bit stuck on how to get the Platinum Chip. I've confronted Benny in the casino, and let him go. I've disguised myself as a member of the Legion and have snuck into Ceasar's tent to find Benny, but no chip. I can't talk to Ceasar because of my reputation with them. Is my only option to kill the Legion leadership to get the chip? And if I do that will that prevent any possible future battle on the dam?

Nope, if you kill Caesar, the story changes by a roughly .5-1% change. A little dialogue change in the end in the fight, and Mr New Vegas mentioning Caesars death, a few NPCs say it in random comments, beyond that, nothing changes, apart from obviously not being able to work for the Legion.

If you let Benny go the chip should have been on Caesar's corpse(he should have taken it from Benny when the legion captured him). I kill Caesar as a matter of principle as soon as the quest unlocks the barge npc...I had actually spent a couple hours trying to find a way over to Fortification Hill on my first play through with no luck. That was a lot of swimming. So you can kill that S.O.B. regardless of which faction your working for, save, of course, Caesar's Legion.

After Benny flees from the Tops you should have been approached by one of the Legion. He gives you the Mark of Caesar, which stops them from being hostile to you so you could walk into his camp and talk to him. If you have Boone with you this won't work, however, as Boone makes them hostile. So leave Boone at home.

Or perhaps you can try and continue the NCR line. That is skip the chip. :whisper: