In stark silence, they paid tribute to a man who should have been there, but was instead fighting for his life.
Thursday night, the hospital says Congressman Steve Scalise's condition has improved, but he's still critical. A single bullet shredded his internal organs and splintered his bones, causing serious internal bleeding.
For the first time, the family of the gunman broke their silence. Susan Hodgekinson said her husband James, whom she calls Tom, was down on his luck and unemployed, and had gone to Washington to, in her words, "Change the tax brackets."
She last saw him months ago, when investigators say Hodgekinson drove to Washington and wound up living in his van in Alexandria.
He was staying just steps from the baseball diamond where he staged his ambush attack. Investigators are still trying to figure out what set him off.
Related: Video shows 5 minutes of terror at baseball field in Alexandria
"I can't believe he did this. I can't believe. I just want you all to go away," his wife said.
Back at the game Thursday night, it was a show of unity, one of the injured officers threw out the first pitch.
Despite unprecedented security, more than 20,000 people spent more than a million dollars on tickets. It is all to raise money for DC charities.
Among those in attendance was Joe Coyne from Long Island.
"I'll be watching the Mets game on my phone, rooting for the Mets," Coyne said. "Honestly, I just want to see a bunch of people that don't know how to play baseball in a big field."
As the House returned to business, lawmakers sought some semblance of normalcy even as they offered prayers for the wounded and echoed the president in pledges of unity. Two Capitol Police officers sustained relatively minor injuries, as did a congressional aide, and they have been released from hospitals. But a congressional aide-turned-lobbyist, Matt Mika, was shot multiple times and critically injured, and he remained hospitalized.
While top lawmakers, including Scalise, have security details, others do not and they regularly appear in public without protection. Democratic Rep. Gabby Giffords of Arizona was hit in the head and grievously injured while meeting with constituents at a supermarket parking lot in 2011.
(Some information from the Associated Press)