again check the facts
the population of illegal immigrants in the U.S. has gone down while President Obama has been in office.
the number of illegal immigrants coming across the border has also gone down while President Obama has been in office
the number of border patrol agents patrolling the border has gone up while President Obama has been in office
If the population of illegal immigrants has declined (a dubious proposition), it is only because economic prospects for Mexicans are better in Mexico than in the US during the Obama Depression.
The Obama plan to ship jobs to Mexico is working.