Alexis Haller, uncle of Noah Pozner, one of the children killed in Newtown, poses for a photograph at Lafayette Park while Noah's sister, Danielle Vabner and brother, Michael Vabner, chat in the background. (Katherine Frey/The Washington Post)

On Dec. 14, Alexis Haller was on the phone working on a legal brief for the Vatican when his mother texted him to say that there had been a shooting at Sandy Hook Elementary School in Connecticut. His nephew was missing.

Haller, a litigator in Washington state, monitored the news and felt his stomach drop when reports emerged that an entire classroom of children had been killed. Confirmation of the worst came later that day. His nephew, Noah Pozner, 6, had been shot 11 times at close range with a semiautomatic weapon, making him the youngest of the 26 people slain that day at the school.

One month later, Haller found himself in Washington, D.C. On Wednesday, the soft-spoken 39-year-old with rimless glasses and exhausted eyes sat in the front row of an auditorium in the Eisenhower Executive Office Building as the president and vice president announced new gun-control measures. Haller had crafted and forwarded several proposals to prevent future gun violence that were shaped by his experience as a lawyer for the Holy See. He also had publicly criticized the administration for what he considered an initial failure to reach out to victims and their families. In a political environment in which victims are often used as backdrops for a photo opportunity, Haller decided to use his awful status as an opportunity for advocacy.

“The thing my whole family on my sister’s side latched on to right away was we have to make something positive come out of it,” he said.

Before heading to the office building on Wednesday morning, Haller grabbed a pair of socks off the wall of clothier Jos. A. Bank. He had flown in late the night before, and the airline had lost his luggage in Burbank, Calif. An aide to Vice President Biden had offered to lend the visiting lawyer her husband’s blazer, but Haller preferred to shop for his own clothes. While sifting through suits and ties (“My nephew’s favorite color was blue”), he talked about his family’s “nightmare” month.

President Obama formally unveiled new gun-control polices Wednesday, and referenced several of the most violent shootings of the past few years. (The Washington Post)

On the night of the shooting, Haller arrived in Connecticut to help lighten the logistical load for his sister, coordinating with a state trooper assigned to meet the family’s needs and establishing a Web site to collect donations to pay for counseling and education for Noah’s siblings, including his twin sister. He received an expression of support from the Holy See, met President Obama at Sandy Hook (“He was devastated”) and eulogized Noah at his funeral (“He would have become a great man”). When Haller’s wife, an active blogger, learned that a fake account had been set up in Noah’s name, the Princeton- and Stanford-educated Haller decried the scam on CNN’s “Anderson Cooper 360.” The FBI thanked him, Haller said, for preventing more fraudulent activity.

Haller returned to Seattle on Dec. 28 to meet a deadline on the Vatican brief, but made time to talk to school-safety experts and read the Secret Service report on the shootings at Columbine High School. As he pored over research, he kept finding incidences of “leakage,” a term describing when a person intentionally or unintentionally reveals clues that may signal an impending violent act.

“It got me thinking,” Haller said, “because in the Vatican cases, I have done extensive work on child abuse statutes and reporting statues in particular.” One of the consequences of child sex abuse fallout in the Catholic Church is that bishops are now expected to report predator priests to authorities — something that Haller said was also on his mind as he thought about gun violence.

When he first took on the Vatican as a client a dozen years ago, he researched sex abuse laws and learned that in the 1960s, as X-rays became more widespread, doctors could see broken bones and realized that parents were beating their children. A public outcry resulted in the first reporting statutes.

“How can you justify having a reporting requirement when you have reasonable cause to believe a child is being neglected” but not, he said, “when you have cause to believe that 20 children are about to be slaughtered? That makes no sense.”

On Jan. 2, Haller e-mailed a member of Obama’s staff whom he had met during the president’s Newtown visit and who had encouraged him to share his ideas and concerns. He followed up the next day with a phone call but heard nothing. Haller and his sister, Veronique Pozner, then took their frustration public, releasing a statement that was picked up by news organizations. “As the mother of a six-year-old victim of a cold-blooded massacre of school children, I am puzzled and disappointed by the fact that I have had no information or opportunity to be heard regarding the upcoming legislative proposal in Washington,” Haller’s sister wrote.

That night, as Haller was driving to a television studio for another appearance with Cooper, he received a call from Biden’s office, blaming miscommunication for the failure to reach out and asking him to please relay his ideas.

Noah Pozner was one of the victims of the shooting in Newtown, Conn. (MC.Farine)

“Based upon my conversations with the vice president’s office,” Haller said, “it appears that some groups may have been purporting to represent all of the victims’ families when that was not, in fact, the case.”

On Jan. 13 — after finishing the Vatican brief and celebrating his son’s sixth birthday — Haller woke up at 4 a.m., walked downstairs to a home office and wrote out what he called the Sandy Hook Reporting Law. It would require any person who has knowledge of a grave and imminent threat of serious physical harm or death made by someone with access to a gun to notify law enforcement authorities within 24 hours. “Failure to report in accordance with this statute is a misdemeanor punishable by up to six months of confinement,” Haller wrote.

A second proposed measure came out of conversations with his sister, who was enraged that the gunman’s mother had not kept guns out of the hands of her troubled son.

“As a former criminal defense lawyer, my reaction was, ‘Well, we need to make that criminal,’” Haller said, adding that under his proposal, if Adam Lanza’s mother “had survived, she should have been prosecuted and she should have gone to prison.”

“The White House has been in touch with Alexis and other families in Newtown, and we value their input,” said Elizabeth M. Allen, a Biden spokeswoman. “There is no perspective more meaningful to this discussion than families who have lost children to tragedy.”

Haller left the D.C. clothing store wearing an almost-matching gray jacket and pants. He met Noah’s 18-year-old sister, Danielle, and 17-year-old brother, Michael, who was impressed by how his uncle had been “able to form so many connections.” The trio walked over to the Executive Office Building, where Obama and Biden greeted them and vowed that they were determined to make a difference.

Haller and his family took their seats and received handshakes from Obama adviser Valerie Jarrett and Homeland Security Secretary Janet Napolitano. Behind them sat John Feinblatt, the point man for New York Mayor Michael R. Bloomberg’s organization Mayors Against Illegal Guns, many of whose proposals the president adopted. Haller nodded in approval as Biden spoke about the “incredible courage” of relatives in attendance. Obama said that of the many groups he has met with, “none have affected us more than the families of those gorgeous children.”

After the event, Haller met with Biden’s staff to discuss recommendations on reducing gun violence. “I feel like they are getting serious consideration, based on what I can tell,” he said of his ideas. “And I guess we’ll find out more over the next couple of days and moving forward.”