Heading into the all-important back-to-school and holiday shopping seasons, U.S. retailers as a group are struggling. Same-store sales among the 31 retailers that report such figures fell an average of 6.4% in the month of July, as the worst downturn since World War II continues to savage consumer confidence.

"You still have a picture of the consumer remaining under pressure and having fewer dollars to spend," Michael Dart, senior partner at Kurt Salmon Associates, said in a Reuters interview. "Every consumer group is being more practical and more budget-conscious."

The two leading indicators of U.S. consumer sentiment – the Reuters/University of Michigan index of consumer sentiment and the Conference Board’s confidence index –show that consumers are not yet ready to return to the level of extravagance that helped keep the economy humming before last year’s financial meltdown.

However, instead of creating an environment in which all retailers are wheezing – with the sickest patients on the financial sector’s equivalent of life support – there’s been a major divergence of fortunes for two main types of retailers. The discounters are faring relatively well – especially given the dour backdrop. But the high-end retailers – including some of the U.S. economy’s heavyweights – are struggling badly.

The bottom line: The retailers with the best “value proposition” have fared the best throughout the recession. With the prospect of a jobless recovery looming, that trend will likely continue for at least the remainder of the year.

Expect the health of the retail sector to be a key topic this week as the next round of corporate earnings are released – this time for Macy’s Inc. (NYSE: ), Nordstrom Inc.