> A switch to proportional voting could require constitutional changes in most places.
Less places than you might think. It especially wouldn't for Congress (so long as it was proportional by a method similar to STV within state delegations, or within some subset of state delegations), as the only barrier there is a statutory prohibition on at-large districts for delegations greater than 1, adopted to head off the use of FPTP at-large districts to systematically deny representation not minorities.
> Also, proportional voting introduces all kinds of unnecessary problems like not having districts
Party list proportional would do that, but most other proportional systems would not.
> and thereby constituents having their votes diluted
Proportionality doesn't dilute votes; the more proportional a system is the more efficiently it allocated votes to give them maximum effect.
> and not having a specific representative
Proportional systems don't need to have that effect, either, no matter how you measure it (and FPTP—and any other simple singlr-member district system—definitely has that effect for supporters of the nonwinning party in a district, who are effectively unrepresented entirely.)
It causes your vote to be mixed with a larger number of other votes, which is the definition of dilution. By giving the candidates more alternative constituents to win over in order to stay in office, your vote is less important to them and there are more ways they can screw you over and still stay in office.
> the more proportional a system is the more efficiently it allocated votes to give them maximum effect.
That isn't inherently true. Suppose you have a state with two districts. 60% of the state are religious conservatives, 30% are libertarians, 10% are socialists. With proportional representation the socialists get disenfranchised because they don't get their own candidate. Even the libertarians might get disenfranchised if the religious conservatives manage to get two representatives. But with range voting, you end up with a candidate who has to make all the interests in their district as happy as possible because anyone who comes along and can make them happier would defeat them in an election -- so nobody gets disenfranchised because every victor needs to make everybody happier than anybody else.
Proportional systems also fail in the same way but worse when forming governing coalitions. Suppose you have a White party and a Black party and the White party voters are 70% of the population. Then proportional representation gives them 70% of the representatives, they form the majority coalition and the Black party representatives lose every vote.
Compare this to range voting where if you so much as have a White party, they lose even in many majority-White districts against a moderate candidate who can earn the support of both White and Black constituents. It promotes the election of moderates with broad appeal over the election of extremists who fight to gain a majority coalition that can steamroll over anyone in the outgroup.
Less places than you might think. It especially wouldn't for Congress (so long as it was proportional by a method similar to STV within state delegations, or within some subset of state delegations), as the only barrier there is a statutory prohibition on at-large districts for delegations greater than 1, adopted to head off the use of FPTP at-large districts to systematically deny representation not minorities.
> Also, proportional voting introduces all kinds of unnecessary problems like not having districts
Party list proportional would do that, but most other proportional systems would not.
> and thereby constituents having their votes diluted
Proportionality doesn't dilute votes; the more proportional a system is the more efficiently it allocated votes to give them maximum effect.
> and not having a specific representative
Proportional systems don't need to have that effect, either, no matter how you measure it (and FPTP—and any other simple singlr-member district system—definitely has that effect for supporters of the nonwinning party in a district, who are effectively unrepresented entirely.)