4) Connecticut
Under the Castle Doctrine, Connecticut permits the use of physical force in defense of one’s premises.
An excerpt from the law reads:
A person in possession or control of premises, or a person who is licensed or privileged to be in or upon such premises, is justified in using reasonable physical force upon another person when and to the extent that he reasonably believes such to be necessary to prevent or terminate the commission or attempted commission of a criminal trespass by such other person in or upon such premises
Force can only be used if the “defending” assailant believes that the alleged aggressor is “using or about to use deadly physical force, or, inflicting or about to inflict great bodily harm.”
You can find the full legal language here.