PFPTP ProFirst means that it would always be worth voting at a general election, even in a very safe seat, because:
- If the candidate considered most likely to be elected in your constituency is the one you would support, even if you may not fully support that candidate's party, then your vote will go to increase the candidate's voting power as an MP
- If you do not want to support the candidate most likely to win, then by giving your vote to the party you would most favour - even if that party's candidate is unlikely to win in your constituency - you are increasing the voting power of your preferred party's MPs who have been elected in other constituencies.
- It involves no boundary changes, because constituency size does not matter in terms of evening-out the voting power of the parties by ensuring that constituencies have roughly the same population. And it would be impossible to adjust boundaries to gain partisan advantage: so "gerrymandering" cannot affect the national result. A party gaining one extra seat purely because the constituency boundary was drawn in its favour would still have the same total of votes, but divided among more MPs, each of whom would therefore have a slightly smaller voting power.
- It gets PR without losing the important MP/constituency link, so that every MP is still responsible to and for a constituency, everybody would still have their usual constituency MP, and there would be no multi-member constituencies and no "list" MPs.
No vote would be wasted in “safe” seats, so many more people would vote, while people in marginal seats would now only have the same effective voting power as the rest.
PFPTP ProFirst should also greatly reduce or even eliminate "tactical voting", because:
- It is better to support the party you really want, rather than to vote in favour of another party that you would not normally support. Voting tactically is merely trying to prevent the candidate considered most likely to win in your constituency (or that candidate's party) from being voted-in.
- Under PFPTP ProFirst, voting "tactically" would be largely counter-productive. It would actually have the effect of increasing the voting power of the party whose candidate you voted for tactically but did not really wish to support, and would deny the use of your vote in Parliament by the party you would have preferred to support. And PFPTP ProFirst would also mean that if voters' intentions changed during the course of a parliament, then that would be reflected to some extent in the parties' relative voting power as a result of by-election "swings".
- While it is impossible to tell until the system is tested in the real world, it seems quite plausible that the promise that votes for losing candidates in safe seats would no longer be totally wasted would discourage voters from frittering their votes away as a protest on "loony" or extreme candidates whose party is very unlikely to win a single seat nationwide. So are there any disbenefits?