If I am logged into KDE and press the power button briefly, I am logged out of KDE, however, the system does not shut down. Is there a means to change this behavior? I would like the system to shut down when I am logged in to KDE and press the power button.
This would be in your systemsettings application. As in menu / Personnel Settings or menu / Configure Desktop, depending on your KDE desktop version and then Hardware / Power Management. You should find “When Laptop Lid is closed” and “When Power Button is pressed” there.