The rich and powerful have coined a name for them. They're called the Precariat. These are blue and white collar workers who work full time for meagre wages that leave them in a state of constant precarious economic vulnerability. They're dependent on their next paycheque. It's all that keeps them from plunging, along with their family, into poverty. Noam Chomsky wrote about this growing class and their plight in Huffington Post.
The venerable, Brookings Institution, no hotbed of pinko radicalism, has just published an essay entitled, "A Dozen Facts About America's Struggling Lower-Middle-Class."