Hillary Clinton testifies before House Benghazi panel Thursday. The Wall Street Journal is ready with this viewer's guide.

Most movies and TV shows would kill for the kind of advance publicity the House Select Committee on Benghazi had gotten, free of charge, for its grilling of Hillary Clinton on Thursday. Not all publicity is good publicity — as committee chairman Rep. Trey Gowdy (R-S.C.) has lamented — but the consensus in Washington is that Clinton, Gowdy, and their respective parties all have a lot riding on Thursday's testimony. Clinton will likely try to make the committee look like a political hatchet jo...