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.
The possibility of impeachment shows a general limitation on the power of the president.
This means that a president is not immune to any kind of punishment, as an impeachment proceeding may remove him from power once the allegations thrown at him/her will be proven true.