Grillo is collecting signatures for three related petitions (which have purely moral force): one to bar convicts from standing for parliament, one to introduce term limits for parliamentarians, and one to reintroduce preference votes for individual candidates.

The best part is, he mailed all parliamentarians asking them for their positions on these three petitions, shaming them into responding by taking a non-response as a negative response.

The responses on preference voting are the most interest. A full list of  responses is here. Break-down:

• more centre-left deputies replied than centre-right deputies;
• 121 votes in favour of preference voting (61%), 62 against, 14 ‘other’;
• Centre-right: FI 5/13 (38%); AN 8/16 (50%);   LN 2/4 (50%); UDC 7/9 (78%);
• Centre-left: PdCI 5/9 (55.6%); Ulivo 39/68 (57%);  Rif. Comm 10/17 (58.8%);  Sinistra Democratica 9/14 (64.3%);  Udeur 3/4 (75%); Verdi 6/8 (75%); RnP 4/5 (80%); IdV 15/16 (94%)

Conclusions? Two types of parties support preference voting: ex-democristiani (Udeur, UDC) and self-consciously reformist groups (IdV, RnP, Verdi).

Opposed quotes from former allies:

Gianfranco Fini 

The preference vote allows voters to chose. But it’s undeniable that, in the past, through the enormous financial resources necessary, campaigning for preference votes nourished corruption. To allow voters a better choice I would rather have single member districts.

Marco Follini
I completely agree with the third point [preference voting]. I tried on a thousand occasions to have preference votes alongside the proportional law.  I think that it is necessary to give parliament back to the voters, and that the best way of doing this lies precisely in reintroducing preference voting.