The people behind the National Popular Vote (NPV) are well-intentioned voting reformers. And so are the voting reformers advocating better voting methods (e.g. range voting) to replace our present very-flawed "plurality" voting system. Indeed, these two kinds of people often are the same people. For example, Rob Richie, a prime mover behind the "Instant Runoff Voting" advocacy group fairvote.org, is listed as a co-author of the national popular vote book.
However, despite their good intentions, these reformers are about to deal themselves a devastating self-inflicted blow because these two reforms, unless careful attention is paid to the matter (which it apparently hasn't) will conflict and may permanently destroy each other.
But what is the "national popular vote winner"? The proposed NPV-compact legislation we've seen nowhere defines the term! Now you might say "it doesn't need to be defined because its meaning is obvious." Wrong.
The difficulty is if some state, thanks to the efforts of voting reformers, adopts a different voting system than plurality voting, such as instant runoff voting, approval voting, range voting, or a Condorcet system. Then what?
Several massive problems then immediately erupt.
Our point is, any way you look at it, voting system reform is converted into a house divided against itself, unable to stand, and wildly shooting itself in the foot; and also into a political football.
It sounds like the solution is simply to insert into the NPV compact, now, language indicating exactly how to deal with other voting systems. That way all signatory states know exactly what they are getting into ahead of time, supreme court litigation is unnecessary, and "voting reform" is no longer an "evil plot" but rather "a known, good, predictable, and predicted, development."
But writing that language is not trivial. Different kinds of voting systems in different states simply were not designed to be agglomerated to yield one overall "popular vote winner." The electoral college itself can be regarded as a way to do such combining in a sensible manner – but that is precisely what the NPV compact is trying to get rid of!
A number of principles need to be adopted in the writing of such language:
Here is a set of counting rules which obey these principles. (Actually there is a way that the proposed rules for IRV and Condorcet could disobey the discontinuity or responsiveness principles, but those exceptions are unlikely to arise and even if they do are likely to be small in their effect and only likely to affect non-winner candidates.) We recommend these be inserted into the NPV compact's language immediately:
Note: with IRV and Condorcet, it is best if (whenever more than one compact-state uses the same voting system) all the votes in all those states be agglomerated into one mass then counted to determine the IRV or Condorcet winner of the resulting super-state. One reason for that is that IRV is a non-additive voting system in which X can win in both state #1 and state #2, but if we combine the votes from both states then Y wins. With additive systems like range, approval, and plurality, this issue is irrelevant because the same results always happen whether you agglomerate or not.
Problem 1: Suppose the countrywide popular vote is for A, but nearly all (or anyhow some) of the states in the Compact prefer B. In that case those Compact-states would, by obeying their own rules to make A win, be acting against their own interests!
Problem 2: The compact will have no effect until and unless enough states join it to get a clinching majority.
Problem 3: Why should a state S join such a Compact?
Don't believe this? OK, here's why CA governor Schwarzennegger said he vetoed CA's inclusion in the Compact: "I appreciate the intent of this measure to make California more relevant in the presidential campaign, but I cannot support doing it by giving all our electoral votes to the candidate that a majority of Californians did not support." (You'd think after the biggest state in the USA dodged the compact for precisely the reason we said, the NPVers might listen to us and adopt the simple fix we propose. Just in the interests of their own survival. You'd think.)
Problem 4: If a state outside the compact adopts a new and weird voting system (not in the list above), it can still unilaterally destroy the compact!
Simple Solution to all 4 problems: Make the compact cast a bloc vote for the popular vote winner among the compact's member-states' combined population only, and make it do so no matter how many (or few) states have joined the compact. This way, nonmembers cannot free-ride. Hence states are motivated to join the compact. Further, the compact, even well before it has a clinching majority will often be able to throw the presidential election due to the power of its solid bloc vote. Even with only a few states joining the Initial Compact, it will be an 800-pound gorilla that presidential candidates will pay immense attention to. Nonmember "shirker states" who fail to unite with that gorilla, will do so at their peril; presidents are not likely to pay much attention to the shirkers. Hence the motivation to join, will be major.
If our suggestions are adopted, the NPV compact will be like the "Borg." It will, once it gets rolling, be very hard to stop, since all will be motivated to join it. Indeed, to make a historical analogy: the initial adoption by the states of "winner take all" electoral voting (which is just like the NPV compact idea, only writ smaller) grew in a similar fashion – nobody could afford not to do it that way and hence become irrelevant.
(Serious students: please also see the Deeper analysis of compact-growth process and worries.)
But there is one way it could quite plausibly be stopped. The US constitution says:
"No State shall, without the Consent of Congress, [stuff about war omitted], enter into any Agreement or Compact with another State, or with a foreign Power ... "
They explicitly mention "another State" and "foreign Power," so clearly the first is meant to mean a State in the US and not as a generic foreign power/nation/state.
I.e, states are allowed to have compacts, but only with the"'Consent of Congress." There was a ruling that for minor agreements between States, Congress' consent can be assumed if Congress doesn't take explicit action against it. But this seems to imply that Congress has veto power over compacts – and quite possibly they would be moved to exercise it in the case of NPV!
That would get us into a delicate "state's rights" issue. Although the above quote seems to indicate clear veto power, it also is quite arguable that congress cannot veto this because congress does not have the power to tell states how to assign their electoral votes.
We do not know what would happen to that constitutional battle if fought. But let us say this. Even if such a "veto" does occur and it is sustained – shooting down NPV – then NPV could still have played the useful role of bringing voting-methods issues to public attention. That possibility makes it doubly important to implement our recommendations!