The feud within the Le Pen dynasty that has ruled France's National Front (FN) for four decades is teetering between high drama and a low farce that could emerge as the biggest threat yet to the far-right party's quest for mainstream power. Party founder Jean-Marie Le Pen's defense this week of his view that Nazi gas chambers were a mere "detail" of war has prompted Marine Le Pen, FN leader since 2011, to demand his role in the party be discussed at a meeting FN executives Friday. The blood line linking the two, plus the family talent for invective, make this no ordinary political row - to the glee of rivals who have seen the FN gain from the rise in support for populist parties in a Europe just emerging from recession. "Let's hope this runs and runs." Marine Le Pen has sought to rid the FN of its anti-Semitic image and position it as an anti-immigrant, Eurosceptic force offering protectionist economic policies to shelter ordinary French from the vagaries of globalization.