What Were Newt's Ethics Violations Anyway?
In short, when he was teaching in Georgia during the 90s, he taught a class called "Renewing American Civilization," which was funded in part by a non-profit (tax exempt) organization. For several years, Newt's Democrat opponents investigated whether the class was political and therefore, should not be funded by a tax-exempt organization. Newt settled the matter by paying a fine. The IRS later concluded there was no wrongdoing.
Romney can criticize Newt for a bunch of things, but this one is absurd.