Mitt Romney called for an expansion of parental choice in America’s school system Wednesday, pivoting to a subject he has discussed little so far in his presidential campaign.

Mr. Romney spoke in Washington, taking his message on education to a city that is home not only to his electoral rival – President Obama – but also to one of the nation’s important experiments with school vouchers.

He criticized Mr. Obama for failing to pursue deeper education reforms, saying the president has been “unable to stand up to union bosses, and unwilling to stand up for kids.”

“As president, I will pursue bold policy changes,” said Romney. “Dramatically expanding parental choice,