Requiring voter ID disenfranchises marginalised and poor voters, who may not be able to obtain ID easily. I know several people who have no form of government issued ID.
It's different in countries like Germany and France, where compulsory national ID is a thing.
Rates of fraud and abuse are low enough that this isn't an issue. Technically I could go and vote in somebody else's name, and hope they also didn't vote, and I most likely wouldn't get caught. But if they did vote as well, then the double-vote would be noticed (people have have been caught casting multiple votes in the past) and would be investigated.
If the office that hands out ID cards is only open 9-5 Mon-Fri, for example, a voter who must work during this time and can't afford to miss work may not be able to get ID.
(Not a conjecture, this was actually evidence in one of the various voter ID lawsuits; the state government had constructed a table with impact assessments of various approaches, then picked the one with the worst impact)
https://fivethirtyeight.com/features/what-we-know-about-vote...
To be clear what I don’t buy is voter ID having a suppressive effect iff we had an actual national ID
IMO, it's bloody retarded that this feature is still non-present in the US, resulting in all the pseudo ids like driver's licenses and SSNs.
https://fivethirtyeight.com/features/what-we-know-about-vote...
In the UK you must pre-register for a single voting location, and then when you turn up to vote they cross your name off so you can't come in again.
> I think this is a big part as to why postal voting fraud happens.
It might happen, but it is exceptionally rare. The impact of introducing voter ID laws would cause a far larger decrease in election validity due to voter suppression than postal voting fraud causes.