the ndp is arguing for a mixed member proportional system, and while the liberals have been a little confusing (as they tend to be), their most recent attempt was the single transferable.

mmp has been repeatedly rejected by plebiscite. it's not a popular option. personally, i'd be happy to see them move to the stv, but the perception is that it will cement the liberals in place. correct or not, it's a problem in it's adoption.

www.theguardian.com/world/2015/aug/03/canada-election-parliament-stephen-harper