Rep. Trey Gowdy is a man under fierce pressure. He's chairman of a congressional Benghazi investigation that's dismissed by Democrats as partisan and even questioned by Republicans.

No matter.

The former prosecutor and three-term South Carolina Republican known for his "Southern politeness" is pressing ahead. He's determined to get the facts about the long night of Sept. 11, 2012, when extremists hit two U.S. facilities in Benghazi, Libya, and killed four Americans, including Ambassador Chris Stevens.

On Thursday, as chairman of the House Select Committee on Benghazi, Gowdy faces Hillary Rodham Clinton.

The former secretary of state and Democratic presidential candidate will be the star witness in the 17-month-long, Republican-led investigation that already has surpassed the 1970s-era Watergate probe in length.