Thats what I was referring to when I said I disagree.
He does not have the kind of hold on the district a Ralph Hall or Richard Shelby long-time Dem would have. -- I don't think disagreement on this point is reasonable. It would be extremely rare for a pol in office one year, especially one who has received so much criticism from both sides, to have the popularity of a long-time incumbent.
If he had run as a dem, he would have lost. -- Griffith's district was rated one of the most vulnerable Democrat districts. I think it exceeedingly unlikely that he would have been renominated and elected while constantly attacking and apologizing for his own party, angering his Democratic base and making Republicans realize they could just elect one of their own who wouldn't vote for Nancy Pelosi.