Protip: Dan O'Connor is more ideologically pure than Karen Kwiatkowski.
O'Connor says he supports free markets. He gave his definition of free market in an article on the free market Internet:
“If patent-protection laws, taxes, and legal-tender laws were completely eliminated from the internet, we would then see a purely free market.” http://mises.org/daily/3766
The worst that can be said of O'Connor is that he supports school vouchers.
The worst that can be said of Karen Kwiatkowski is that she supports the Fair tax.
O'Connor wins.
Kwiatkowski is more ideologically pure than Thomas Massie, though. She's probably about as pure as Art Robinson.
It's tough to judge Richard Mack's purity vs. Kwitkowski because Mack avoids certain subjects. I haven't found anything wrong with Mack, just that there were a few holes (mostly economic), last time I checked.