The Chilean senate is no longer completely terrible but ...

In 2015, Chile reformed its horror of a Senate. (This blog is no fan of senates.)

Previously, Chile elected two senators from 19 constituencies. Eight of the constituencies conformed to Chilean regions, regardless of population. The remainder consisted of regions split in half. In every constituency, the party that won a plurality would get one senate seat. Then the runner-up would get the other seat, unless the winning party more than doubled its vote share over the runner-up. This is the binomial system Andrei mentioned in comments.

That system is now mostly gone, replaced with one where each Chilean region gets a number of Senators proportional to its population. Inside each constituency, Senators are selected by proportional representation. 

But it is still terrible. Consider the below chart. The horizontal axis is the number of senators from each constituency. The vertical access is the population of the constituency. Five of the smaller ones are stuck with the old binomial system. And the distribution of senate seats is lumpy and only vaguely related to population. 

Moreover, smaller regions are ridiculously over-represented and metropolitan Santiago is massively under-represented. Consider:

So the Chilean senate is still a mess. But the lower house is even worse!

There is actual is actual overlap, with smaller districts getting more deputies that larger ones. Malapportionment is terrible.

In other words, the 2015 amendments may have (mostly) abolished the binomial system, but they still left districting a mess. Multimember districts are a good thing, but this is a terrible way to do it. Chile needs constitutional reform.

Although I am still not clear why it needs a whole new constitution. Thoughts?

Comments

[Ben]

Hi Noel -

I wrote a piece trying to address exactly why Chile does need a whole new constitution, rather than just continued reform.

It's here if you have any interest:
https://notesfrompatagonia.substack.com/p/chile-and-the-ship-of-theseus

Thanks for your interesting posts,