Heffer's Law

Definitely in action here:

Finally, it was not the banks that brought down our economy: it was the last Government's refusal to regulate them properly, and to moderate the supply of cheap money that allowed them to lend so much so recklessly.

Banks, you see, are a force of nature and cannot be expected to reach optimal decisions about risk-taking on their own. Therefore any mistakes they make are directly attributable to those who fail to stop them.