No security system is foolproof.

Nothing is foolproof to a talented fool.

Not as something that was foolproof, but as an idea to think about.

Taking a long walk by yourself, during which you devise a foolproof scheme for robbing Tiffany's, is serious.

We've watched the financial markets that we uniquely create these markets that were supposed to be foolproof we've watched them kind of collapse before our eyes.

Traditional lab tests for disease diagnosis can be too expensive and cumbersome for the regions most in need. George Whitesides' ingenious answer, at TEDxBoston, is a foolproof tool that can be manufactured at virtually zero cost.

At a time when a growing number of countries were mastering the technologies for the production of fissile materials and nuclear devices, export controls and the safeguards system could never be foolproof in deterring all proliferation.

Such plans, however, are by no means foolproof not least owing to the difficulties of finding concealed nuclear assets and safeguarding reactors. Moreover, the American public s willingness to become enmeshed in yet another risky military venture, when boosting homeland security could suffice, is dubious, at best.

In the end, there is no foolproof method to guarantee that political leaders leave without tears. What matters is that mechanisms are in place that do make them leave, probably rather too late, and certainly with some pain and unhappiness, but in time for the constitution of liberty to remain intact.

Larry Summers, now the highly influential director of President Barack Obama s National Economic Council, concluded as a young economist that financial and monetary shocks are less important sources of depression than we had suspected. If the economy was foolproof, and if so many good policy options existed to deal with crisis and distress, there was less need to avoid mistakes.