My point is that, while the SNP obviously don't have enough seats to vote down legislation, what they can do is add a heck of a lot of depth and value to debate. If they can argue compelling and constructively against the right hand side of the Tories, they could significantly sway the more centre-ist members, against the whips. But that will only work if they don't alienate non-scotts MPs at Westminster by focusing on devolution to much. We need the union to moderate the right...