Americans have been using their credit cards a lot less and their debit cards a little more, and that adds up to bad news for "big-ticket" Christmas shopping-dependent retailers, says Janney Montgomery Scott retail analyst David Strasser, in a report today using data collected by payment-systems analyst colleague ThomasMcGrohan.

Credit card use (in which shoppers borrow from banks) has been dropping since last fall at Visa and MasterCard. Debit card use (in which shoppers use their own money) is up, but a lot more slowly.

For every $2 less they use their credit cards, shoppers are spending less than $1 more on their debit cards.

Total U.S. credit card debt peaked at $975 billion in fall 2008, and dropped below $900 billion this summer. Charges fell more in August than in any prior month of the slowdown, falling $20 billion.

As Strasser notes, banks are "pulling back on consumers that were not creditworthy, or cutting the lines of consumers that were marginally creditworthy." Maybe forced savings, or at least less debt, will be good for the nation, over time. But this "bode(s) poorly for the holiday season and early 2010, particularly for big-ticket items that are credit dependent, as well as for retailers that are heavily dependent on middle-income customers."