I am amazed that I am the only one who has seen such an incident. It was a short hop from STL to ORD. A slightly drunk passenger on a delayed flight began to argue with a FA and ended up standing up, getting in her face, and pushing her backwards in the aisle. Once the situation got physical, the FA simply walked away, spoke to the cockpit and sat down until the plane landed.

Once the plane pulled into the gate, the pilot came on the loudspeaker and told the passengers that it would be a few minutes until the door would be opened at which time I saw (from my First Class seat) two uniformed US Marshals come on to the plane and take the rowdy passenger off in handcuffs.

These incidents do happen and they are often dealt with swiftly and decisively.

Hope the story gives you a good example.