For decades, Ted Kennedy was the whipping boy of conservatives but after he dies he was sainted, praised widely as a lion of the Senate. But that period's over. In the course of bashing Mitt Romney, Newt Gingrich and others took off after the late Senator. Rick Santorum dissed the late Kennedy and another sainted Senator, Daniel Patrick Moynihan.
Maybe this is still red meat for Republican primary voters, but somehow I doubt it. Democrats were using Herbert Hoover as an epithet as late as the Mondale campaign in 1984, more than 50 years after FDR had whooped him. (Mondale dissed Reagan for being the first president since Hoover not to meet with his Soviet counterpart. Of course, in his second term, Reagan seemed to sign a major arms control agreement with Mikhail Gorbachev every other week.)
All of this is more proof of why Romney is winning. If Gingrich is hauling out Ted Kennedy, he's not pushing the debate forward. Same with Santorum. Romney went after him too which was probably a mistake but he at least gets to say he actually challenged Kennedy.