Hillary Clinton is on the defensive on foreign policy for the first time in the Democratic primary.

Clinton is a forceful presence on foreign policy and very good at defending her record as secretary of state, as she proved during the Benghazi hearing. But for the first time in this election season, she’s being challenged by Democrats on foreign policy. That’s a very different dynamic than the Benghazi hearing, where the Republican focus on esoteric conspiracy theories made her look good. Against Sanders and O’Malley, she’s having to to defend something larger: her foreign policy vision, which led her to support the Iraq War and later made her a strong advocate for intervention in Libya and Syria. Sanders made a palpable hit by noting the problem with regime change as a policy goal. There are strong echoes here of Obama’s successful challenge of Hillary Clinton in 2008, where sharp differences in foreign policy visions defined the characters.