Jeff Rank and his wife, Nicole, were arrested July 4 at a Bush rally in Charleston, W.Va., for wearing shirts that read "Love America, Hate Bush" and refusing to relocate to an area for protesters. Earlier this month, at a Bush event in Cedar Point, Ore., Janet Voorhies and two friends were ejected for wearing T-shirts with "Protect Our Civil Liberties" printed on them.
"I think this represents a low point in public discourse in this country, where the mere sign of disagreement is intolerable to candidates," Post said. "That can't be right. That can't be American."
A Kerry staffer at an Oct. 24 Kerry rally in Boca Raton, Fla., told Bush-Cheney T-shirt wearers that the campaign held a permit to rent the site and could remove anyone who made a disturbance.
"We hold the right to remove you, but other than that, enjoy and hopefully at the end of the event you'll want to wear a Kerry T-shirt," he said.
One thing the rallies had in common were the taunting remarks the opposition's T-shirts drew.
"We're not allowed in your party, because your party's exclusive and stupid," said one Kerry supporter at the Minneapolis rally.
A Bush volunteer said at the Melbourne event, "You guys know you have to love America to stand in this line, not France. Just letting you know. I don't want you guys to get beat up in there by Americans."
Post said that First Amendment laws most likely did not apply to these rallies, as the ticketed campaign events in private venues would be seen legally as private affairs.
"But what does apply are the basic morals of politics," he said. "And the morals of politics are, we talk to the people whom we want to convince. That's how we get votes. We convince people to vote for us, and we give them reasons when they disagree."
And at Kerry's Boca Raton rally, one of the faithful Democrats could be seen calming a woman upset at the sight of the Bush-Cheney T-shirts.
"Feel proud that we let them in," he said. "That's what democracy is all about, that's what we're fighting for."
ABC News' Vic Walter, Jessica Wang, Christine Romo contributed to this report.