A liberal blogger filed a complaint against Thompson saying he abused the “testing the waters” rules. Having researched and written about this a bit I’d say there’s more than a little merit to the claim. However, as a practical matter, the FEC takes eons to investigate these issues (and the penalties are rather minor) so any action or settlement would likely occur sometime into the next president’s first term. As a political matter, the downside of the extended testing phase I think has outweighed any benefit Thompson derived and that, if anything, will be the only political penalty paid. A liberal media complainant filing just weeks before Thompson declares anyway isn’t going to do any damage to him. Pundits and his opponents may grouse that he played all the angles like a Washington pro but this is not going to mean anything to the average voter. That said, I’d bet in the future very few candidates will try this gambit of an extended testing phase.
UPDATE: It seems Thompson may not get a pass on this from his opponents. From a rival campaign: “All the ah-shucks in the world cannot explain the utter hypocrisy of Fred Thompson’s interest in transparency and disclosure as a champion of McCain-Feingold-Thompson in the Senate and his apparent interest in skirting the law as he stumbles towards a presidential bid.”