Aaron Alexis destroyed lives and caused serious damage to others on Monday during his shooting rampage at the Washington Navy Yard.
But the broader damage that he inflicted was exposing a gaping hole in the Navy facility's security and possibly similar holes at other U.S. military installations.
Security measures need to be beefed up, to prevent anyone not authorized to have a gun or guns in their possession from entering such a facility.
Meanwhile, as could be expected, the incident reignited the debate about stepped-up gun controls and registration requirements - a debate that will wane until the next time multiple lives are snuffed out by a shooter.
The only possible positive product of Monday's unwanted tragedy would be effective steps to close, or at least narrow, the security gaps that Monday made apparent.
Alexis' success at bringing guns into the facility is indicative that terrorists could find a way to do likewise, possibly with relative ease.
For navy yard employees and contractors, Monday's horrific episode might make getting to work each day a more time-consuming process, but that might be necessary going forward.
Whatever the result, Monday no doubt will be the impetus for some changes that will be forthcoming. Perhaps this nation's military facilities are safer even today than they were at dawn two days ago, due to the horror that Alexis wreaked.
As for Alexis himself, there was an error in him having been issued a government ID tag that authorized entry into the navy yard. He even had "secret" clearance.
His background was not fully investigated.
Likewise, there was a failure by his employer to take into consideration his past brushes with the law and his discharge from the Navy Reserves for a Navy-stated "pattern of misconduct," before assigning him to work at the military facility.
That is not to imply that someone without such a questionable background could not have chosen to do what Alexis did on Monday.
However, the likelihood of so many serious security mistakes coming into play would have been lessened, and the message - exaggerated or not - about porous security at military facilities would not have been delivered.
Still, it's safe to say that enemies of this country know more about military base security lapses here than most Americans are willing to admit.
Tuesday's report that Alexis had been receiving treatment from the Veterans Administration for mental health issues was further confirmation that not enough was done to factor in his past to what he was doing in the present, especially in regard to a work setting to which he should not have been granted access without more scrutiny.
Despite what might be implied, it's too early to make absolute judgment about whether military installations actually are safer today than they were pre-Alexis.
However, those who hate America are no doubt watching intently as a more detailed picture about the Alexis tragedy continues to emerge. Beyond the glee that those enemies harbor, they will be assessing possible opportunities for doing harm to this country in the future.
Alexis is dead, but the impact of the slaughter he carried out remains to be determined.