Is Mr Romney fecklessly attempting to mobilise the conservative base, somehow ignorant of the fact that his right flank is already plenty motivated? Perhaps Mr Romney, terrified by a small, probably temporary drop in the polls, insanely gave up all hope of victory in a still very close race a solid three months before the election, threw caution to the wind, and took a flyer on a tea-party sweetheart. Or maybe it's that Mr Romney, predicting his electoral defeat three weeks in advance of official nomination as his party's standard bearer (on the basis of something only he knows, such as his flagging will to live, let's say) picked Mr Ryan as part of a provident, pre-emptive blame-shifting scheme .

Amid this racket of balderdash Nate Cohn sounds a gentle note of reason:

I find it hard to imagine that the Romney campaign volunteered to walk down the plank. As I’ve said before, I do not assume that campaigns make cataclysmic strategic errors, and the Romney campaign undoubtedly tested this extensively and still felt comfortable picking Ryan. 

Too true! Indeed, Mitt Romney is a very smart man who has enjoyed some success in politics. This oddly overlooked fact leads me to suspect that Mr Romney, after intensively investigating his options, and knowing full well that the vice-presidential candidate tends to exert, at best, a small influence on the outcome of presidential elections (even when he or she hails from a swing state), simply came to believe that Mr Ryan would make a superior running-mate and, if it comes down to it, vice-president. Sometimes the simplest explanation really is the best.

To my mind, the most salient lesson of the last two days of political commentary is that presidential candidates are wise not to ask politically unsympathetic journalists to choose their running mates.