I don't think there is any answer to that. If you look at the Australian Senate, for example, where an equal number of senators are elected from each state, it votes entirely on party lines. The protection of the states from which the senators are drawn, if it's a consideration at all, is an awfully hard consideration to discern. And similarly, our own Senate typically votes on party lines. Now, they'll often give up in the end, because they recognize that they are not an elected body and shouldn't frustrate the House of Commons on other than the most important things. But I think the influence of party tends to be inconsistent with the protection of regional interests.
On April 16th, 2008. See this statement in context.