{{Infobox Television episode | Title = Why We Fight | Series = Angel | Image = | Caption = | Season = 5 | Episode = 13 | Airdate = February 18, 2004 | Production = 5ADH13 | Writer = Steven S. DeKnight Drew Goddard | Director = Terrence O'Hara | Guests = Eyal Podell (Lawson) Lindsey Ginter (Cmdr. Petrie) Scott Klace (Initiative Man) | Episode list = List of Angel episodes | Prev = You're Welcome | Next = Smile Time }}

"Why We Fight" is episode 13 of season 5 in the television show Angel. Sam Lawson, a mysterious man from Angel's past, arrives at Wolfram & Hart and takes Wesley, Fred and Gunn hostage. In a flashback to 1943, it is revealed that Angel was forcibly recruited by the Demon Research Initiative to recover a captured German U-boat with American sailors on board. The ship also has a secret cargo of three vampires: Spike, the Prince of Lies, and Nostroyev, who were kidnapped by a Nazi team. The submarine is damaged, and Lawson, the only surviving engineer, is mortally wounded. In order to save the rest of the crew, Angel makes Lawson a vampire (seemingly the only one he sired between 1898 and 1998) and forces both Lawson and Spike out of the submarine to swim to shore. Sixty years later, Lawson seeks out Angel for revenge.See List of Angel episodes for a complete list.