So if the FO is being an idiot, or doing something he's not supposed to, like texting during ground ops, are you saying the Captain can't do jack?

The only times I had to lay down the hammer was when one moron kept on turning the pressurization on and off to screw with the people on the back, at which point I sent him to the back to sit with the CO and brought a NFO up to be a copilot, and when I was flying helicopters, we had this one dude who liked to flip random switches, valves and levers to "see if it does what NATOPS says will happen", without briefing it, at the worst possible times.

The rest was minor stuff like we're 30 seconds from landing, put the damn soda down and get a visual on your gear.