Renault-Nissan deal could spur other suitors—and not just with GM...

So far, there's nothing in the proffered Nissan-Renault overture to buy part of GM to indicate it's anything but friendly. But even this mild-mannered gesture could lift the lid off a box of snakes.

A rival suitor could ante up a better offer. At some point, GM's Board of Directors might launch a spirited, even ugly, defense. And talk of a GM deal might stimulate merger or takeover offers to cross-town rival Ford Motor Co.