&gt; It fails otherwise it would still be valid.<p>You&#x27;re confusing things. The validation fails, as in it doesn&#x27;t meet a certain requirement, the certificate; it isn&#x27;t damaged or otherwise broken.  A mechanical object fails in that it takes physical damage. You&#x27;re striving for some semantic technicality to save your argument and I just don&#x27;t think it&#x27;s important.<p>&gt; An expired certificate is clearly a lower risk than a revoked certificate, so only having one failure mode regardless of cause is unnecessary.<p>Why? You&#x27;re just throwing an assertion out there that is false and expecting me to believe it&#x27;s true. Additionally, if there is a 2-day window where an invalid certificate is valid, then all that does is make the expiration date 2-days into the future.  If the certificate&#x27;s owner doesn&#x27;t notice an invalid certificate until after  it doesn&#x27;t validate, then they won&#x27;t notice until after the window anyway.<p>&gt; PS: With an expired license the number of days past expiration is important in most states. Wait long enough and you need to retake the driving test, so clearly before that point it&#x27;s still somewhat valid.<p>That doesn&#x27;t mean an expired license is valid.  That simply means there is an implicit expiration date for the validity of your driver&#x27;s exam.