Truly, I get some of the rare pleasure from my PM job when stakeholders balance their own needs. Sometime your silence will cause others with a different view to offer it up, and a discussion starts. You just keep it on track, and affirm the outcome. IF they're going in a bad direction, just insert a comment from time to time to keep them on track.
If that doesn't work, I take the "Yes" approach. I tell any of them they can have what they want; besides they're the stakeholders (ie customers), not me. BUT I make them take the consequences with what they want.
"Sure we can ship it 3 months sooner, so long as you're good for another 5 FTEs in your customer support group to address the new alls that will be coming in.
"Sure you can have that feature, so long as you sing this change request putting it up in the priority stack, above the CEOs' favorite requirement. Do you want to go talk with him first?"
you get the drift... PMs get in trouble when they assume responsibility for something for which the authority hasn't been granted.