Trade votes with voters from swing states
pbs.org
pbs.org
That said, anything that allows you to prove who you voted for is a flaw in the design of the voting system anyway, so to the extent that there are loopholes that allow this, one would hope that they will be fixed.
As for reputation - reputation systems rely on the ability to verify that something has already been completed. If you order something online and never receive it, you are able to complain and cause reputational damage to the seller. In the case of vote-swapping, you shouldn't ever be able to know whether or not the other person voted the way they said they did, so you never actually know that the other person is untrustworthy.
Edit: Porter v. Bowen was a federal Appeals Court ruling, so it isn't a SCOTUS-level, nationwide decision. But it certainly establishes precedent, and could potentially be used by those who wish to challenge any state laws that expressly prohibit vote-swapping as a restriction of their First Amendment rights.
Technically, tampering. Yet-to-be-adjudicated in the same way as someone doing something illegal doesn't always get prosecuted because stare decisis (or political backlash) is so crazy-overused that you rather avoid going forward than lose on technnicalities or by a small margin.
PS: The article you linked dates from 2000. Porter v. Bowen was in 2007. You really ought to check the dates on things you read. A lot has changed in 16 years. Look at Citizens United.
Vote-swapping is not a new thing. There's even case law that supports it as a clear exercise of one's First Amendment rights. See Porter v. Bowen. You might not like it, but that has no bearing on its legality.
Apparently I'm not the only one making strong claims today.
What jurisdictions outside the Ninth Circuit have expressly forbidden the practice of vote-swapping? I've performed a cursory search of US laws against vote-pairing and vote-swapping. I have found nothing. Please, share your knowledge of what parts of the US have enacted legislation that makes non-pecuniary pairing/swapping illegal.
Based on what evidence I can find, I'm making no strong claims. Please point me in the right direction to revise my understanding, if it is indeed in error.
https://popehat.com/2016/11/05/randazza-vote-swapping-trump-...