[EM] A simpler approval based way of replacing the CA jungle primary
robla at robla.net
Mon Jul 23 15:03:06 PDT 2018
Andy and Kristofer, thanks both of you for weighing in on this.
Kristofer: thanks for teaching me about the "maximum coverage
problem". It's been a lonnnng time since I've been in a C.S./math
class to study that sort of thing. But since I'm an unrepentant
packrat, I was able to find my textbook from when I was in C.S.
learning about similar problems (e.g. the four color theorem). The
Wikipedia article was way more helpful :-D Andy, I suspect your
hunch is correct; if "2 advance" is all we compute, that doesn't seem
too difficult to achieve via brute force algorithm.
As I've been mulling this over and talking with other folks, I have a
hunch based on a number of assumptions:
1. The top-two primary system is ripe for reform
2. Change-averse voters want typical two candidate elections to
include 1 Democrat, and 1 Republican, since that will seem most fair
to them. Change-averse Democrats don't mind when only 2 Democrats
advance to the general, and change-averse Republicans don't mind when
only two Republicans advance to the general, but the unfairness of the
current system outrages them when the opposite party prevails.
3. Many of those change-averse voters dislike the top-two primary,
for reasons described here:
4. Many voters prefer having two elections (a primary and a general)
and dislike efforts to conflate public consideration of candidates
into a single all-purpose election
5. Many voters also don't mind having a diversity of choices *in the
primary*, and dislike onerous restrictions on ballot access
6. There are many voters who abstain from voting in the primary
election, but vote in the general. I'll refer to them as
"general-only voters", General-only voters appreciate having a
simplified choice in the general election, and are frustrated by
having too many non-viable options that haven't been culled out.
My hunch: a ballot initiative focused on primary elections only is
more likely to be successful than one that attempts to modify the
general election. As I've been mulling the large 22-week gap between
the primary and the general election here in California (in 2018, the
primary was Tuesday, June 5, general election is Tuesday, November 6),
I think the following could be a viable an incremental reform:
A. All candidates who receive over 50% approval qualify for the general election
B. The two candidates approved by the most number of voters *also* qualify
C. After the primary election, all qualified political parties have 28
days to endorse their preferred candidate. Said endorsement is
required in order for a candidate to list the political party next to
their name on the ballot
D. After the primary election, all qualified candidates have 7 days to
accept/reject any official party endorsements. Any accepted party
endorsements will be listed next to their name on the ballot.
E. Also 35 days after the primary election, qualified candidates may
withdraw their name from consideration in the general election. As a
result of withdrawing, their name will not be printed as a candidate
in the general election.
Once again, some intentional ambiguity. In the scenario I laid out in
my July 18 message: A-left, B-center, and C-right would all advance
(what Kristofer referred to as an "LCR situation"). Assuming the
Democratic/Republican duopoly still held, B-center would then be in a
good position to broker for the endorsement of either the Democrats or
the Republicans. If none of the candidates drop out, then it's a
classic 3-way plurality race.
I think this LCR situation would be rare. I believe a much more
common case would be that only one candidate gets over 50%, and that
that candidate is also part of the pair who qualifies in step "B"
above. Thus it would be rare for three candidates to advance when
only one achieves 50% approval. Moreover, in this system, all
candidates would be motivated to achieve >50% as their top priority to
guarantee a qualified spot on the general election ballot.
However, I wouldn't want to ignore the general election drama problems
that this system might create. If this were proposed via ballot
initiative, I think some non-binding latitude+guidance that should
explicitly given to the state legislature should be:
a. the ability to alter the general election, such that it *also* is
tallied via approval voting
b. the ability to amend this, making the approval threshold lower for
advancing to the general election (e.g. "40%" or "30%" rather than
c. the ability to amend this, making it so that if only one candidate
gets 50% approval, they automatically win the general election (thus
making it a single-step approval election)
d. the ability to amend this, making it so that the candidate
receiving the highest approval score wins the election, thus
consolidating the primary and general elections into a single
All clauses above would make the glide path toward approval voting in
the general election clear, while making a change that even
change-averse voters can get behind (since the core of the initiative
would be a change to the top-two primary). If my hunch #4 above is
correct, then some combination of clause "a" and/or clause "b" will be
the more popular alternative. If I'm wrong, and most people like the
idea of having a single election to replace the primary+general system
we currently have, then clause "c" or even "d" will be the most
Does this proposal make sense, or is it too complicated to be viable?
On Thu, Jul 19, 2018 at 7:10 AM Andy Jennings
<elections at jenningsstory.com> wrote:
> On Wed, Jul 18, 2018 at 4:37 PM, Kristofer Munsterhjelm <km_elmet at t-online.de> wrote:
>> On 2018-07-19 00:26, Rob Lanphier wrote:
>>> There are many ways of dealing with this:
>>> 1. Only allow 2 candidates to advance, keeping with the spirit of
>>> "top two", and use simple plurality in the general election.
>>> 2. Have higher limit (e.g. 5 candidates) and only allow the top 5
>>> approval getters to advance. Tally the general election using
>>> approval voting > 3. Choose the 5 candidates for whom at least one is approved.
>>> Calculating this seems complicated, but the goal would be the 5
>>> finalists would be A1-left, A2-left, A3-left, B-center and C-right.
>>> Once again, tally the general election using approval voting.
>> If I recall correctly, choosing the candidates to maximize the number of voters who approve of at least one of them is NP-hard for general n. See https://en.wikipedia.org/wiki/Maximum_coverage_problem.
>> The best you can do without P = NP is a very obvious greedy algorithm (successively pick the candidate that maximizes the number of additional voters covered by the set of candidates so far). The greedy algorithm makes it relatively easy to start with one or more candidates picked by other means (e.g. the Approval winner) and then filling in the rest.
> I believe runtime is exponential in the number of winners, so "2 advance" and "3 advance" are quite tractable, and "5 advance" should be possible in most cases.
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