Hendrik Hertzberg repeats a very common claim about the Democrats and 2016:

A footnote: Hillary Clinton’s prominence points up the remarkable shallowness of the Democratic bench. Whether or not she chooses to run, the supply of plausible alternatives is shockingly thin.

This gets things backwards. Whatever the quality of other possible candidates, the fact is that virtually no one talks about any other Democratic politicians this way because Clinton is presumed to be the overwhelming favorite. That is, the “bench” appears shallow because Clinton’s presumed frontrunner status crowds out any interest in other possible candidates, and so no one ever bothers to entertain the other possibilities. Because virtually no one promotes these other would-be candidates, they remain obscure to the rest of their party and the country at large, and that is bound to discourage many of them from even considering the idea. It’s also more common for people to speculate about candidates from the party out of power, and when the sitting president has three years left in office there is less incentive for ambitious members of the president’s part to express interest in the position.

The assumption that Democrats have a “shallow” bench for presidential candidates reflects an odd difference between the two parties. On the Republican side, there is a tendency to speculate about the presidential prospects of almost any elected official with a pulse. Movement conservatives spend an inordinate amount of time building up and comparing possible candidates years in advance, and this then filters into other media coverage. No matter how lacking in qualified presidential candidates the Republicans may be, movement conservatives usually deem their “bench” to be overflowing with available talent. The big complaint in 2012 wasn’t that the Republican “bench” was shallow, but that the “best” candidates stayed on the “bench” instead of running. Warren is receiving some of the same treatment right now because she happens to be a favorite with some progressive activists and pundits, and they are drawing attention to her because of specific policy views that Warren has that they want to see promoted within the party.

This week’s possible Republican presidential candidate happens to be Scott Walker, but it shouldn’t be very long before another politician is chosen more or less at random to be treated to speculation about presidential aspirations. It is rare for something comparable to happen on the Democratic side, which is another reason why the list of possible Democratic candidates seems so much shorter than the other party’s.