What is meant by prosecutorial discretion?

In all the conversations related to Deferred Action Process for Young People Who Are Low Enforcement Priorities (DAPYP or pronounced as DayPip), you might be reading everywhere this term and wondering what it means.  So here is the simple explanation:
  1. Regardless of whether you call yourself undocumented or illegal or DREAMer, the reality is that you have broken US law.  That is why, by default, you can be prosecuted for this crime.  By submitting your application to the USCIS, you are submitting yourself to leniency by a prosecutor.  In other words, it is entirely up to the prosecutor to defer action on your deportation and grant you a work permit to find legal employment.
  2. Why this complicated process?  Only US Congress has the authority to approve an amnesty.  What President Barack Obama did was to direct federal prosecutors to defer action on prosecution in the hope that Congress will eventually pass the DREAM Act.  Thus, in the eyes of the law, you can be prosecuted for this crime at any time and even deported, and this is a distinct possibility if another president does not extend this benefit or DREAM Act is not passed.  Right now, however, the shortcut that the president has found to grant this benefit is that he is directing the prosecutors that as long as an applicant meets the all the eligibility requirements, she or he should be legally allowed to work for a period of two years at a time.  In summary, it still means that the prosecutors or the decision makers in each case will exercise their discretion to approve each case.
  3. It is also good to know that while your past crime is not being forgiven in any way and it will always be on your record (unless Congress specifically condones it), your unlawful status could come to haunt you your whole life in the United States.  Actually, by taking advantage of the Obama plan, you are admitting wrongdoing and providing documentary evidence of it to the authorities.  Do not be surprised that this application can be used against you at any time.