You are aware that there are countries that manage to run elections on sundays and with sufficient polling places to not have any lines to speak of at all? That might be too advanced a technology for the US, but, unbelievable as it may sound, countries like that do indeed exist!
First of all, I didn't say that you should, I just pointed out that your argument didn't make a whole lot of sense.
But also, the reason why voting by mail is problematic is, as has been mentioned, the potential for pressuring people into voting a certain way, including buying of votes.
Now, you said that this had been studied and it had been found that it's not really been a problem. But that's completely missing the point. You cannot judge the security of a system against attacks simply by looking at how many attacks were successful in the past. A voting system being reliable is most important when shit hits the fan. That it works fine when stakes aren't (perceived to be) all that high isn't really all that surprising, the most easily corrupted voting systems would probably work fine, and it tells you absolutely nothing about how it would hold up under different circumstances.
Also, mind you, objectively giving an accurate result is not the only function that a voting system has in a democracy, equally important is that the public trusts the system and thus the result, and trust erodes really fast under the wrong circumstances, which is when you can consider yourself lucky if you have a voting system where fraud is not just not happening, but where you can demonstrate that it's not happening.
To maybe get an idea of how stuff that's not actually secured is going to be exploited once the incentives are there: In the US, the relevant laws generally don't specify how to divide the country into voting districts. Because nobody thought of that as a problem when writing the law. Nowadays, gerrymandering is a reality. It's obviously undemocratic (I suppose you would agree?), but it's not illegal, and the incentives are there, and so it happens. There is almost nothing that people don't do for power. Trusting that people will be responsible when there is an opportunity to gain power is essentially the recipe for every major disaster humanity has ever created.
There are theoretical problems with any system of voting, everything's a trade-off one way or the other. Vote-by-mail increases turnout, it's easier and more convenient, and the problems you're afraid of simply don't happen in practice.
At the end of the day, I'd much rather have the increased participation in the democratic process than cater to the unfounded/theoretical fears of a few folks.
It's not at all theoretical. Postal voting is heavily restricted in Northern Ireland due to past history of paramilitary organisations influencing voter behaviour.
One needs to provide an attested reason for not attending the polling station:
You must provide a reason why you cannot reasonably be expected to vote in person at your polling place on polling day. You must provide exact dates and locations (if applicable) or the application may be rejected on the grounds that not enough detail about the reason has been provided.
Oregon isn't Northern Ireland. They might have had problems with voter coercion. Oregon hasn't. Oregon has had problems with turnout. This improves them.
