There are only 22 countries left in the world where voting is compulsory and only a few of those are countries that have good reasons for that rule.
As soon as your country appears in lists that also contain 'North Korea', 'Congo', 'Lebanon' and 'Thailand' when it comes to political matters you really have to wonder if you're on the right path.
The only countries imo which have a legitimate reason to make voting compulsory are those that are so small that the statistical basis underlying the decisions taken based by the people voted for would be removed.
A vote is a 'poll' just like every other and you don't need a 100% sample in order to reach statistical significance.
I'd be very suspicious of any elections that did have 100% turnout.
In my mind, there are two points about compulsory voting that are nice: 1) The government must make voting available (various Republican-lead areas in the US are trying to reduce voting hours to limit voting for poor and minority voters) 2) Employers must make it possible for employees to take the time to vote (no consistent protections currently)
I'd take compulsory voting in the US just to say "fuck you" to the various groups that have been disenfranchising female, poor, and/or minority voters for generations.
Those organizations probably would embrace compulsory voting without making it easier for the targetted groups to vote in practice, because they'd probably see being able to punish them for not voting an extra bonus on top of disenfranchising them in the first place.
I mean, do you think campaigns would stop blanketing neighborhoods expected to vote for the opposing candidate with false information about voting times and locations if the payoff went from "they don't vote, improving our chance of winning" to "they don't vote, improving our chance of winning, plus they are compelled to pay fines for not voting"?
Voting is a fundamental right to self-expression and self-determination. And I think that any attempt to prevent a citizen from voting or preventing a legitimate vote from counting (barring votes that are unable to be interpreted) should be considered treason.
Lots of the suppression tactics that are like this (as opposed to the suppression-disguised-as-anti-fraud efforts) are already federal crimes. Doesn't stop them from happening.
Making voting compulsory wouldn't change this (nor would it stop people from proposing anti-fraud efforts that make voting more difficult in practice. Just because voting is compulsory for people who are qualified doesn't mean that there aren't non-citizens and criminals who are forbidden to vote, and that you can't sell bureaucratic "safeguards" that make it more difficult for qualified people to prove that they are qualified in order to vote as mechanism to prevent the unqualified from voting.)