“Maybe I am just following Dina D’malchusa.”
While the extent of Dina Malchutcha Dina is debated among poskim, none argue that it overrides explicit Torah commandments. See below.
“the states are generally very liberal about allowing you to shoot intruders”
But is HaShem so liberal? I haven’t studied this extensively, but according to some opinions you must give the intruder a warning, and the permission to kill the intruder only applies if it is not possible to stop him with a non-lethal wound (or, possibly, escape). I’ve seen that attributed to the Remah.