The Judicial branch may <em>annul </em>the laws of the state that are not compatible with a higher norm. Its responsability is to <em>apply</em> the law in the name of the state and to ensure equal justice under law.
The government is divided in independent and separate branches to provide a balance and avoid only one power dictating decisions.
Because as the times change the way people view certain actions tend to change. This means that justices will often times use previous events that happened under similar circumstances as their standard. Hope it helps :)
