Obama’s #1 goal is re-election and he needs Hispanics to get off their couch and vote again as in 2008 and things are not well in the Obama-land economy. This is intended to motivate them to vote. Notice they call it 'temporary' two years, that means another administration (assuming we had a party who cared who gets elected) will know who all these people are and COULD take action.
It seems like a pretty safe move for Obama to do this a few months before the election, the chances of a high profile crime by one of these people being publicized before the election is low, but many Hispanics with illegal relatives will be grateful, as well as the illegals themselves that vote illegally.
During the debates you can bet the Obama Media (who asks the questions) and Obama will put Romney and Ryan on the spot on two different issues.
1) What will you do about those “immigrants” who under President Obama have been granted temporary Amnesty?
2) What is your stance on gay marriage and gays in the military?