I don't think that VDH was suggesting that we let "Europe fall". I think that he is merely suggesting that we recognize that European & US interests are diverging and we need to accept that new reality.
Those interests have always been divergent. We should be concentrating upon dealing with "Europe" on a country by country basis and forget the EU superstate (and the UN with it). The principle of accountability Hansen is citing needs to be driven downward.
In that regard the French present a unique problem. It would seem that they gain their status only by "virtue" of their craven willingness to engage in abject perfidy. By disengaging them from Europe at large, we might just focus the world upon the depth of their depravity and thus induce some substantive change for the better.