Why would you immediately think about using a gun, even as a leverage tool, at the first sign of a confrontation? If you even hint to the aggressor that you're packing you run the risk of him ceasing the confrontation and calling the police to report that you pulled a gun on him. An "in between" step might prove useful here. Something like O.C. (pepper spray) Maybe brandishing O.C. could de-escalate the situation?
"But today you just read that the man was shot dead
By a gun that didn’t make any noise
But it wasn’t the bullet that laid him to rest was
The low spark of high-heeled boys"
~Traffic - Stevie Winwood~