kardynalny błąd

But then we asked him a bit more about it and he made his fatal mistake.

He was making the fatal mistake of trying to hold all his ground.

The effect was to make it his war more than the country's, a fatal mistake.

A man needed only one fatal mistake to end the game.

Of course, it may be a fatal mistake to think that she can ever read him right.

It was then that I made what might have been a fatal mistake.

Many another man has done the like, and made as fatal a mistake.

"Especially not after the fatal mistake I made last time."

How had he allowed himself to make such a fatal mistake as to fall in love?

And that may be just the fatal mistake he expected.