If we're just thinking of ways voting can be corrupted, in-person voting can be coerced too. Boss forces you to take a photo of your ballot as you vote in the booth, etc.
In reality, several states have had mail voting for years- Oregon for decades- without coercion being a problem. Millions of votes cast without the problem you suggest. It's not a problem, despite using our imaginations to come up with ways it can be.
> Boss forces you to take a photo of your ballot as you vote in the booth, etc.
You can take a picture of the ballot with your boss's choice but then spoil it and get another one.
> several states have had mail voting for years without coercion being a problem
How do you know this? How could anyone know if a wife voted the same way as her husband because she wanted to or because he just filled out both mail-in ballots himself?
There are differences in scale too; It's hard to steal a ballot, for example, when only 1% of the population is voting by mail. It's easy when 60% of mailboxes have a ballot in them on the same day.
Finally even if it hasn't been a problem so far, it is not a "fact" that it cannot and will not be a problem in the future.
> Finally even if it hasn't been a problem so far, it is not a "fact" that it cannot and will not be a problem in the future.
Twitter said no such thing, however. Twitter's annotation simply noted that Trump's claim was "unsubstantiated". They did not make an assertion of the inverse of Trump's claim.
> How could anyone know if a wife voted the same way as her husband because she wanted to or because he just filled out both mail-in ballots himself?
This could be easily said about in-person ballots too. 8 states require photo ID, and many people will be covering their faces when they vote in-person anyway.
In reality, several states have had mail voting for years- Oregon for decades- without coercion being a problem. Millions of votes cast without the problem you suggest. It's not a problem, despite using our imaginations to come up with ways it can be.