I was listening to the radio yesterday on my way home from work and heard an interview with an MK from Shas discussing whether Shas would support a referendum on the disengagement plan. The MK stated that R' Ovadya Yosef paskened against a referendum. We find the same language used with respect to R' Elyashiv on this and similar issues.
I find this very troubling. This is not a halachic issue. The question is political, does a referendum help or hurt Shas, Degel Hatorah etc. A referendum is no different in the eyes of halacha then the Knesset voting on it. The only issue is does a referendum help or hurt their cause. Many Haredim fear that this will open a pandoras box, that once the first referendum happens there will be further referendums on religious issues (like Shabbos, civil marriage, the draft, etc.) which they will lose. Again, this is a legitimate concern, but not a halachic one and can't be paskened. For the life of me I don't see how a psak can be issued about this.
I see nothing wrong with asking the gedolim their opinion on this issue, they are very wise people, but the bottom line is that this fundamentally a political question not a halchic one.