Meet anyone who is slightly suspect, glib or shifty and you say: "Would I buy a used car from this person?" The question was asked of a haggard, five o'clock-shadowed US president Richard Nixon, and Tricky Dickie was out on his ear weeks later.

But what about a used car bond or even a new car bond, issued by one of the big American manufacturers? Surely you would not hesitate? You can remember, and it wasn't that long ago, when politicians trumpeted: "What is good for General Motors is good for America."