Third brake light question...

OK, I have a Jeep Wrangler and am looking to swap out the rear bumper for a bumper/tire carrier. The only problem with that is I won't have my third brake light anymore. As an aspiring LEO I would rather not run the risk of getting a ticket for it or worse be responsible for being rear ended.

I was under the impression that if it's there it has to work but the third brake light was not required. Please set me straight...thanks.