(Best of the tube tonight: Catch us on "Lou Dobbs Tonight," 7 p.m. ET on Fox Business, with a repeat showing at 10 p.m.) On Slate's feminist blog, "XX Factor," Amanda Hess delivers the news that "mothers are now the primary breadwinners in four out of ten American households." But she doesn't think that's good news, and not because in the other 6 out of 10 households women are still the bread losers. Rather, it's because the poverty rate is higher among women than among men--or, as Hess puts it, "the gender shift in these families hasn't necessarily translated to increased economic...