After a decade marked by deep grief, partisan rancor, war, financial boondoggles and inundation from Hurricane Sandy, the National September 11 Memorial Museum at ground zero is finally opening ceremonially on Thursday, with President Obama present, and officially to the public next Wednesday. It delivers a gut-punch experience — though if ever a new museum had looked, right along, like a disaster in the making, this one did, beginning with its trifurcated identity.

Was it going to be primarily a historical document, a monument to the dead or a theme-park-style tourist attraction? How many historical museums are built around an active repository of human remains, still being added to? How many cemeteries have a $24 entrance fee and sell souvenir T-shirts? How many theme parks bring you, repeatedly, to tears?

Because that’s what the museum does. The first thing to say about it, and maybe the last, is that it’s emotionally overwhelming, particularly, I expect, for New Yorkers who were in the city on that apocalyptic September day and the paranoia-fraught weeks that followed, but almost as certainly for the estimated two billion people around the globe who followed the horror unfolding on television, radio and the Internet. 

Anguished, angry questions about the museum, raised by families of some of the 2,983 people who died on Sept. 11, 2001, and in the 1993 attack on the World Trade Center, have been widely reported. Debates over purpose, propriety and protocol are still in the air. At times, they have threatened to derail the project, or delay it indefinitely. But the work inched forward, and the museum that emerged is true to its initial and literally fundamental goal: to tell the Sept. 11 story at ground zero bedrock...