Scooter Libby didn't intentionally mislead anyone, he just had a bad memory. Went to prison for it.
McCabe, on the other hand, is a low-down, dirty liar.
Scooter Libby was sentenced to prison but didn’t actually go to prison because GWB commuted his sentence (he still had to pay a hefty fine). It isn’t clear if he had a bad memory or just that the prosecutor and the DC jury chose to believe Tim Russert’s recollection of the facts over his recollection.