Get ready for some fireworks on Capitol Hill—and Mark Sanford hasn’t even arrived yet. House Republicans plan on revealing new evidence on Wednesday that they say shows the White House could have done more to prevent the attack on the U.S. consulate in Benghazi, Libya, that killed four Americans, including the U.S. ambassador. A State Department whistleblower is expected to testify Wednesday that former U.S. secretary of State Hillary Clinton was personally involved in the decision not to immediately classify the attack as terrorism. Democrats say the House Oversight Committee’s focus on Benghazi is politically motivated—especially with poll numbers showing Clinton has up to 65 percent of her party’s support if she decides to run for president in 2016.