Many of their suppliers are teetering on the verge of bankruptcy themselves, and do not have the luxury of extending credit much longer.

“I don’t think that suppliers will be able to get through the month without continued payments on their receivables,” said Neil De Koker, chief executive of the Original Equipment Suppliers Association in Troy, Mich., a trade group.

When suppliers big and small start failing, the flow of parts to every automaker in the country will be disrupted because as suppliers typically sell their products to both American and foreign brands with plants in the United States.

The domino theory is incorrect. The correct analogy is house of cards, lose any of them, and the whole thing comes down.