It will depend upon state laws if you can receive a ticket for your tail light being cracked. In many states it is possible that this cracked tail light could cause you to receive a ticket for safety equipment, an equipment ticket or a fix-it ticket.
In many cases it will be a fix it ticket so if you get the broken tail light fixed and prove it to the court then the ticket will be dismissed, though in some jurisdictions there may administrative or court costs to pay. With a fix it ticket most drivers will get the safety issue of the cracked tail light or headlight taken care of quickly so that they can get the ticket dismissed.
I know last year when I was rear-ended and my tail light was cracked, though the light itself still worked as you described, the police officer that responded to the accident and wrote up the crash report told me to keep a copy of the accident report in my car until the light covering was fixed so in case I got pulled over for this I could show that the accident just occurred and that I would was working with the other person's insurance to get it fixed as soon as possible.
To see if in your state you can get ticketed for the cracked tail light covering check with your local law enforcement officer or your state's Department of Motor Vehicles.