In 2013, Bhutan held competitive elections for its National Assembly, using a system that just might be unique.
The election was conducted in 47 single-seat districts, in two rounds. However, the first round was actually a primary in which votes were tallied nationwide to determine which two parties would be entitled to present candidates in each district in the final round.
In the primary, the results showed the Druk Phuensum Tshogpa (DPT) winning the most votes among the four parties contesting, with 44.5%. In second place was the People’s Democratic Party (PDP), with 32.5%. The largest of the eliminated parties had 17.0%.
I counted eleven cases in which one of the eliminated parties finished in the top two within a district. The Druk Nyamrup Tshogpa was first in two districts and second in eight, while the Druk Chirwang Tshogpa was second in one. Many of these second-place finishes were very distant, but a few were competitive. (Treat my numbers in this paragraph as just a rough count.)
In the general election, with just the two parties running, the PDP won 32 seats to the DPT’s 15. The vote percentages were 54.9-45.1.
I know nothing about Bhutanese party politics, but it is noteworthy that the DPT had almost precisely the same vote percentage in the two rounds, so the primary appears essentially to have resolved which one of the opposition parties would survive to the general round. It does not look as if any but a very small number of voters from eliminated parties swung to the DPT.
The total number of votes cast in the second round (252,485) was somewhat higher than that in the primary (211,018). The DPT itself grew from 93,949 to 113,927 votes, which is 48.17% of the total turnout differential between rounds, and thus only slightly higher than its initial percentage among primary voters.
The malapportionment of these districts appears to be extreme. Just a couple of examples: the Khamaed_Lunana district had 714 votes cast for the two candidates (and two votes separating them!) in the general election, while Gelegphu had 9,318 votes cast.
There are also elections to a National Council, which also use single-seat districts (just 20, corresponding to provinces and hence even more malapportioned), but in one round and nonpartisan, at least officially. Many of the districts have more than two candidates (and a few have only one). This could be interesting for analysis of voting behavior across the two systems!
(Thanks to JD, via email, for the tip!)