The answer to why redstar would vote for Le Pen in France is essentially the lack of a viable left option. The goal there is "the worse, the better" trolling of the Parti Socialiste. One may disagree, but the fact that this is redstar's position has been very clear for a long time.

How that interacts with democratic legitimacy is more complicated. But again, if you believe France should credibly threaten to pull out of the Euro, who do you vote for? The Euro is the brainchild of the French Socialist élite (Mitterrand, Delors...) And now Hollande has become a supply-sider: The real scandal is France's stagnant economic thinking (Wolfgang Münchau, 19 January 2014)

The third significance lies in the fact that the new consensus spans the entire mainstream political spectrum. If you live on the European continent and if you have a problem with Say's Law, the only political parties that cater to you are the extreme left or the extreme right.

But as redstar has explained, the Front de Gauche tied itself to Hollande's mast before the municipal elections earlier this spring, and so sealed their fate.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman