IRS Commissioner John Koskinen told Congress on Wednesday that even illegal immigrants who didn’t pay taxes will be able to claim back-refunds once they get Social Security numbers under President Obama’s temporary deportation amnesty. The revelation — which contradicts what he told Congress last week — comes as lawmakers also raised concerns Mr. Obama’s amnesty could open a window to illegal immigrants finding ways to vote, despite it being against the law. “While we may disagree about whether your deferred action programs were lawfully created and implemented, we are confident that we can all agree that these programs cannot be...