The West Wing S2E01 --In the Shadow of Two Gunmen (Part 1)
From TVGuide.com:
The Bartlet Administration is in chaos—an assassination attempt has left the White House (not to mention the country) reeling. Who was hit? Was anyone killed? Who did it? And why? The producers won’t say. What they will say, though, is that the episode includes flashbacks detailing how the Administration came to be. Oh, and one more thing: there’s a downed fighter pilot in Iraq.
From NBC:
All the President’s (Martin Sheen) men and women scramble in the chaotic wake of an assassination attempt that leaves some victims fighting for their lives. Meanwhile, as a manhunt continues, the wounded drift in and out of surgery recalling how Bartlet’s team came together during the dark months of his longshot primary campaign. Elsewhere, the press department is hounded by the media for details of the shooting while a military crisis looms in Iraq.