Now, you have to negotiate your way through a construction site of makeshift walkways and steel-piped scaffolding caused by the massive hotel going up on Eighth Avenue. Inside the disco-turned-theatre, on stage, there is more scaffolding—three-tiered, blackened plank paneling cleverly designed by Robert Brill to suggest everything from Ford's Theatre in Washington to the Dallas Book Depository.

It has taken 13 years for the Stephen Sondheim-John Weidman musical Assassins to travel 14 blocks from Off Broadway (Playwrights Horizons) to Broadway (Studio 54)—a rough road, riddled with detours caused by national crises and the difficulty of the controversial material, but, on April 22, at long last, it made its Main Stem beachhead.

"When you see something finally come in for a landing the way this show did with this production, it's just hugely satisfying," said Weidman, who was quick to credit the show's success to its director, Joe Mantello. "Joe just did a great job. He fills the stage. He has made it enormously theatrical. I feel very grateful to him and to all the people who participated in realizing what Steve and I sat out to write in the first place 13 years ago. This production feels like the absolute finished version of what we wanted to do."

Todd Haimes, artistic director of Roundabout Theatre Company which produced the show, was of a similar mind. "I couldn't be happier," he admitted. "In terms of what I wanted Assassins to be, Joe couldn't have done a better job. And it looks so good in the space. It's a great use of Studio 54—it keeps alive the memory of Cabaret, which is nice." (Haimes created a theatre out of Studio 54 to accommodate Cabaret's long run.)

A ritzy set of first-nighters roared their approval and, after the show, winded their way down Eighth Avenue—again through scaffolding and walkways—to the China Club on West 47th for the post-premiere celebration. Its black box ambiance was entirely apt. Those with green tickets were directed four flights up—it could have been three, but it played like four—to the Jade Terrace where even the most jaded were agog at the Manhattan skyline on display. (The room comes with a retractable roof.) Press interviews were done on the second landing, and the serious partying was done on the third.

One terrace table of oohs and aahs represented some hands-across-the-pond Anglo-American exchanging: City of Angels' Tony winning David Zippel did the lyrics for the new Andrew Lloyd Webber musical, The Woman in White, which will open Sept. 15 in London starring Michael Crawford and Maria Friedman; designer Scott Pask created the sets for The Pillowman, the London hit that has been Broadway-dated for October; and Thoroughly Modern Millie's Tony-winning choreographer, Rob Ashford, is off to London soon to set a revival of Forum a-struttin' for director Edward Hall.

Songwriter Maury Yeston, twice-Tony-ed for Nine and Titanic, was leading cheers for Assassins in one corner of the terrace. "If you look at the performers, they're extraordinary," he trilled. "Two of them are Titanic graduates, y'know—Michael Cerveris and Becky Ann Baker. When you have people like that, how can you go wrong? And James Barbour, also. He was wonderfully intense and should be singled out."

Yeston's next? "Death Takes a Holiday," he beamed. "We're going to do it on Broadway next year. I've done the score, and the book was written by Peter Stone. He finished it completely and polished it, right before he died. This will be Peter's 19th musical."

And it will be directed by . . . ? Yeston gestured to the gentleman on his left, David Leveaux, who directed last season's revival of Nine, and the current revivals of Fiddler on the Roof and Jumpers.

Patrick Cassidy seemed to be lone representative of the original Off-Broadway Assassins in attendance. He was accompanying his mom, Shirley Jones. The two of them are in town rehearsing 42nd Street.

"It's so close to my heart, this show," Cassidy said of Assassins. "I'm so glad it's here on Broadway. To see it on that scale and hear it was that orchestra! It was long time coming."

In the original production, Cassidy played the young balladeer who wanders through the show in a narrator capacity. In this version, the character turns into Lee Harvey Oswald—a change Cassidy heartily approves of: "`Another National Anthem' is so clear to me now, more than when I did it at Playwrights—the whole idea that it can happen to anyone."

The creme de la creme of musical theatre actors came out for this Assassins just as they did for the original. In some cases, the casting is just a generational jump from the first cast. It's easy to imagine Barbour in the role originated by Terrence Mann, Leon Czolgosz who's smitten with Emma Goldman (Thoroughly Modern Millie's Anne L. Nathan). "I tell people I have to do Rum Tum Tiger next. The Beast, Shogun—I seem to follow Terry in every role he does," said Barbour. (At least he beat Mann to Jane Eyre's Rochester.)

Becky Ann Baker is the logical 2004 choice to follow Debra Monk as the most improbable, and comical, wannabe assassin, Sarah Jane Moore. "I think the fact that I didn't actually hit President Ford with a bullet makes it a lot easier to be funny," she reasoned. "John Weidman has come up with a lot of amazing things about her that all happen to be true. She did have five marriages. She did have four kids. She did grow up in the same town that Charles Manson grew up in. John really did his homework."

Becky's hubby, Dylan Baker is off to Mexico City to do "Matador," a film with Pierce Brosnan and Greg Kinnear, and play "a secret agent of sorts," as he did in Brosnan's "The Tailor of Panama."

Michael Cerveris, who normally sports a shaved head, dons a wig here to play John Wilkes Booth, and Marc Kudish, who normally has a full and healthy head of hair, shaved his head to play the shooting-gallery proprietor who distributes the guns to assassins and wannabe assassins alike. "Why did I do it? They asked me," he shrugged. But there is a deeper reason for the transformation: "If somebody offers you something that's completely the opposite of the last thing you did on Broadway, I do it." (The last thing he did on Broadway was the uptight, buttoned-down, square-jawed square boss in Thoroughly Modern Millie.) "There's no other show like this anyway. And then to do what I did, which was a huge experiment because, originally, it didn't exist this way. The proprietor opened the show, and that was it. All the other stuff that we did was stuff that Joe Mantello and I came up with."

For a month recently, Cerveris found himself performing Wintertime and rehearsing Assassins. "It was exhausting, but exhilarating, because it was two things that I really loved doing, and they were extremely challenging, and they could not have been more different—except, of course, that I had access to both of them, but that was about it."

Much has been written about John Wilkes Booth, and Cerveris did a deep dive into the research. "I did a lot of reading on him, including some of his own actual writings, which was really fascinating and very helpful in getting inside his mind a bit. I've also watched some of Ken Burns' documentary on The Civil War, just to understand the context."

When Alexander Gemignani walked into the rehearsal room to audition for the John Hinckley role, Pop (the show's musical director, Paul Gemignani, and a conducting show unto himself) politely took a hike and let the lad fend for himself, which he apparently did with considerable effectiveness. He credits costume designer Susan Hilferty with helping him nail the character. "Once I get into those clothes, I am there."

Another first is racked up by Neil Patrick Harris, who previously worked Studio 54 as the Cabaret emcee. The balladeer-turned-Oswald is the first role he has originated on Broadway, and the experience blissed him out. "It felt great," he said. "I was really trying to stay in the moment the whole time. This has been a dream of mine since I was a child—to originate a part on Broadway. I didn't want to be overwhelmed by it all so I just kinda got my work done early and got to the theatre early and took it all in."

The evening's grandest exit is accomplished by Denis O'Hare, who, like director Mantello, is not resting on the Tony he won for last season's Take Me Out. As assassin Charles Guiteau, O'Hare gets to strut and kick his way up a long staircase to the gallows, singing "The Ballad of Guiteau," which, in its razz-a-ma-tazz buoyancy, is not unlike Georges Guetary's "I'll Build a Stairway to Paris" number in "An American in Paris." "I can't tell you how much fun that is to do. I really enjoy myself—and I like the character. He's always trying to better his life. He believes in the American dream and pursues it." Nathan Lane dropped by Sondheim's table to congratulate the composer on the evening. The two are now collaborators. Lane is adapting as well as enacting Sondheim's The Frogs, which goes into rehearsal May 10 directed and choreographed by Susan Stroman. And when he finishes that it will be the film version of The Producers, also directed and choreographed by Stroman, co starring Matthew Broderick and Nicole Kidman.

He says the Nicholas Martin-directed Butley, which he did to much acclaim last year in Boston, is Broadway bound. "It's just a matter of timing. We're aiming for fall of 2005."

One of Cerveris' Wintertime co-stars, T. Scott Cunningham, was in attendance not only to show his support for the actor but also because his old college roommate at North Carolina School of the Arts directed the show. "Joe and I are going back for our 20th reunion next week," Cunningham said. "We both had techie roommates and we switched, without really knowing each other. We just knew that it wasn't going to work out the way it was."

Next, Cunningham heads to D.C. to play Goober in the Cat on a Hot Tin Roof that Mark Lamos is directing with Mary Stuart Masterson, George Grizzard, Dana Ivey and Emily Skinner. The production has been Brick-less since Patrick Wilson bowed out to do a film. Now it's believed the role will be played by Ron Livingston of "Sex in the City."

Mantello's contributions to the current season has been Wicked and Assassins, which collectively is a lot of sympathy for the devil. After taking the summer off, he'll ready for revival David Mamet's Glengarry Glen Ross, another wonderful example of humankind. "It's my specialty," he grinned. "Assassins was one of the best times I have ever had doing a show, even though the material is so dark and depressing at times. I thought the cast gave the best performance they have ever given. I told them afterward, `If I had a notepad tonight, I wouldn't have taken any notes.' You know, sometimes on opening night they can either overshoot or undershoot? Tonight they were right on target."

Probably, no pun intended.