the accusation that democrats have engaged in tea party tampering (really the claim is that democrats have assisted tea party candidates to get on the GOP ballot or otherwise get the GOP nomination) is interesting because of what it says about the electoral prospects of tea party candidates. it's only a "dirty trick" if tea party candidates are a liability for the GOP, not an asset. (that point seems to be lost on dan riehl).
as others have noted, the tea party really has flopped as a political force. tea party candidates haven't fared well in a bunch of elections, they only seem to have a clear record of victory in GOP primaries. and yet by winning the primaries in nevada and kentucky, the GOP has turned what should have been easy wins in those two states into toss-ups. if harry reid holds onto his senate seat (and polls currently have him in the lead), he should thank the tea party movement for saving his ass.