A top supporter of Hillary Clinton struggled to explain on Thursday why the Democratic presidential hopeful is failing to capture Americans’ overwhelming support considering she’s running against a “huckster and a conman.”

During an early morning appearance on MSNBC, Missouri Sen. Claire McCaskill was asked why Clinton isn’t enjoying a larger lead in national and battleground state polls when her Republican opponent, Donald Trump, has refused to release his tax returns, lacks the “same depth in foreign policy [knowledge],” and now faces questions about his charitable foundation’s foreign business ties.