I've been trying to game this out. The only logical explanation is that Putin has spent the last 20 years installing nuclear dead-man switches for himself across Russia, and has taken the entire populace as hostage. Nothing else really explains it. The amount of backlash and isolation Russia is receiving would be enough to incite a coup otherwise. I'm sure that everyone in his inner circle is made well aware of the dead-man switch, and anyone who even thinks about opening their mouth about it ends up falling from a window.