Voting and Two Round System (TRS)

Wiki article "Voting" is pretty good but

it is interesting to note that the secret written ballot used to be called the "Australian ballot." (OHES, p. 480)

also interesting to note that people don't always vote for one of the top two, even in FPTP.

Oxford Handbook of Electoral Systems (p. 681) gives these reasons:

-signaling voters discontent to establishment parties

-increasing the potential bargaining power of their ideal candidate even if he or she is nonviable

and we see that in Alberta elections -- even when a district has elected right of centre MLAs ever since the 1940s, still some NDPs-ers continue to vote -- and continue to vote for the NDP.

the Two Round System (and IRV likely also ) does not push voters to modulate their position.

and in fact under TRS if you know your main choice will get in top two,then you place your vote on another hoping he or she will be in top two and block your arch-nemesis from getting in to the next round.

TRS leads to Left and Right blocks forming, with intra-block competition in the first round and interblock competition happening in the second round.

Because first round is permissive and many also-rans are in it, and the second round is restrictive (with a threshold --majority), a first-round victory cannot assure a second-round victory.

legislator district elections -- "coalition pacts often involve 'gentlemen's agreements' whereby formal or informal specification of the candidate who will compete in the second round and the designation of the party to which the seat will be assigned."

TRS foster multipartism (multipartyism) and penalizes small parties.

coalition building is encouraged so small parties suffer. (OHES, p. 683)