Here is an unfortunate fact of life: the shortest route between any elected Republican and an invitation to a television interview is criticism of another elected Republican. And hey, who doesn’t like being on television? Accordingly, every time any Republican says anything even slightly off kilter – especially a front running Presidential candidate, the media goes looking for other Republicans to pile on their own criticism to make it appear all the more reasonable and relevant, and like dogs waiting for their scraps, Republicans are happy to oblige in exchange for their 15 seconds of fame.

The Democrats, for all their many, many moral failings, understand the nature of this game far better than Republicans. And so, with Hillary Clinton embroiled in a real, honest-to-gosh scandal that even the star-struck media is forced to notice, when all four of Clinton’s likely 2016 primary foes were asked about Clinton’s judgment in using her personal email to conduct State Department business, they fiercely demurred:

But instead of pouncing on the revelations, each of the possible usurpers of Clinton’s presumed place upon the Democratic throne has punted. Instead they have left it to Republicans and the media to sort out the implications of a potential scandal that threatens to reinforce the Clinton family image as secretive and reluctant to play by the rules.

Asked on Wednesday about the hot water Clinton has found herself in, Vermont Sen. Bernie Sanderstold CNN, “I only know what I read in the newspapers, so I just don’t know a whole lot about it. That’s about all I can say.”

It was an oddly muted response from the typically outspoken independent lawmaker who says he is serious about vying for the nomination. Indeed, he has insisted that he would “run to win” if he does enter the race.

But if running to win means questioning, even politely, whether a Clinton coronation is ill-advised, Sanders wasn’t having it.

“You’re not going to be the sixteenth writer who asks me about Hillary, are you?” he scolded Bloomberg’s Dave Weigel on Wednesday. “I know you would not do that. You want to ask me about the state of the economy, unemployment, poverty. You would not ask me about my views on Hillary Clinton.”

Scott Conroy at RCP theorizes that the demurrals of Sanders, Jim Webb, Martin O’Malley, and Joe Biden in turn indicate that Clinton’s alleged primary opponents do not intend to sincerely campaign against Hillary. They merely want to share the limelight with her on the national stage and have the honor of being blasted off the stage by her. Perhaps there is some element of truth to that, although it is difficult to imagine either Jim Webb or Martin O’Malley in such a subservient position.

What is more likely is that Democrats have long ago recognized the value of not playing the game on Republicans’ terms. Elected Democrats know better than to go on the record criticizing another Democrat if that criticism accepts the premise of Republican criticisms of Democrats. As I have noted before, Republicans not only accept the validity of this tactic (criticizing other Republicans on Democrats’ terms), they actively encourage it. Republicans are constantly validating the Democrat chorus about Republicans in general by calling other Republicans “extremist,” “bumbling,” “dumb,” etc. Democrats who are running for President do not call their opponents extremist even when they plainly are. They do not attack each other on the perceived weaknesses of their party (being weak on national security, naive to the dangers of violent Islam, or supporting profligate and corrupt government spending). They leave that to the Republicans.

Which is why they are smarter at this than we are. And it’s why, although they’ve been summarily booted out of office at the State level across the country for being a bunch of worthless and corrupt incompetents, in the high profile national races, they are still competitive or even favorites. They may have malfunctioning moral compasses and bad ideas, but they have really good campaign discipline.