I’ve done many weddings for Police Officers and others in  Law Enforcement over the years. (My son & daughter-law are police officers. I actually had the honor of officiating their wedding many years. That’s also how I began) Here are vows used by one couple based on a popular police television show:

I will always have your back. 

If you fall behind I will wait up. 

I will earn your respect.

And pay you respect every day. 

I'll be your scout, your night watchman, your cavalry.

Your medic, your chaplain.

I vow to do everything to come home every night.

No retreat. No surrender.

You can count on me.