In “If/Then,” Idina Menzel portrays two different versions of the same character Elizabeth, and at the beginning of the musical, I was feeling like two versions of myself as well.  Elizabeth as Liz pursues love, and as Beth goes after a career as a city planner, in order to try to make a difference in the world.  I, Jonathan, initially felt both like Joe and Nathan – as Joe, irritated at the premise, and as Nathan, excited by the promise of entertainment from so much proven stage talent,  with various past successes in Next to Normal, Rent and Wicked.

By the end, we (I) could agree: The way the premise plays out is more intelligent than it at first seems. The entertainers themselves deliver on their promise. It is terrific to see (and hear) Idina Menzel back on Broadway after an absence of nine years.  She is employed wisely — on stage nearly all the time, she’s given songs that emphasize character as much as vocal gymnastics; we must wait for the occasional  full-steam pop arias like “Always Starting Over”; making them all the more flooring.

But this is a story that would have worked better as a novel, or perhaps a serial on Netflix.

We first meet Elizabeth and most of the major characters in a New York City park that set designer Mark Wendland has created to look like how Bloomingdale’s might depict a park for a display of lawn furniture – sleek, abstract, spare, with a big ceiling mirror that rotates, and a backdrop that changes from one pretty color to another.  Elizabeth has just returned to the city after a dozen years in Phoenix, where she followed her husband because of his career.  We first learn of the divergent paths she is about to take from an argument by her new neighbor and instant friend Kate (LaChanze) who calls her Liz, and says she has come back to New York to find true love, and her old college boyfriend Lucas  (Anthony Rapp) a housing activist, who calls her Beth, and says Beth will use her expertise and education as an urban planner to make a difference in the world.

Will Elizabeth follow Lucas to a housing protest or Kate to hear a guitarist in Brooklyn? Will she be the Liz of love or the Beth of business?

The answer in “If/Then” is: Both.  In the park, Liz meets Josh (James Snyder), newly arrived from overseas combat, still dressed in his military camouflage uniform, and immediately smitten with Liz. He’s handsome, compatible and, as it turns out, a doctor, who enlisted in order to pay for medical school.

Suddenly, the scene plays again in an alternate reality, and Beth answers her cell phone this time (Liz didn’t), missing Josh.  The call is from an old classmate, who is now the director of the Department of City Planning and offers Beth a job.

Now right here is a potential irritant: Is the creative team really implying that a woman must choose between a successful love life and a career?

As it turns out, it’s more complicated than this; one could say admirably complicated, as we follow the forked paths that those decisions take Liz/Beth and her friends over the years. “If/Then” is full of surprises.

Yorkey works in the word “cliché” several times into his lyrics for some reason. In the song Hey Kid, Josh sings to his newborn child:

Before your time is done here,
kid of mine, I hope you’ll see
that this life is what you make it—
it’s cliché, which means it’s true

I’m not sure that a cliché is automatically “true,” but Yorkey manages to playfully subvert quite a few musical theater clichés. The originality of “If/Then” is refreshing.

The problem is, if you get distracted for a moment, you might miss a line that signals a turn, or explains a major shift in direction. There’s too much they want to fit in,  more plot twists and subplots than in the average musical – and not just involving Elizabeth.  Lucas gets a boyfriend in one scenario (the terrific if underutlized Jason Tam), for example, but is bisexual/straight in the other – indeed, in love with Beth.  Kate gets a girlfriend in both scenarios (Jenn Colella), but divorces her in one.

Yet, at the same time, the theme gets summed up in song after song.  In one lovely song, “Some Other Me,” Menzel sings:

Somewhere there’s a world where… I ended up in Boston, or some small Alaska town.
To practice law, or neuter cats, or fish the Bering Sea… Those lives are lived somewhere,

By some other me….

Some other me has seen things that no other me has seen.

If I met her i would ask her that one question we both fear: some other me—
how’d we end up here?

But how many times must we hear variations of this? I would have preferred some of this repetition trimmed, and more time spent with the life of the city — what for a lack of a more inviting term we have to call urban planning. There is one terrific number that gives the city its due, A Map of New York, but otherwise, what Beth does for a living seems mostly to exist as a (weak) counterpoint to what Liz does – as if the theatergoers can only understand or appreciate a relationship between two people rather than a relationship with the environment all around us. I have seen theater that has dealt with just such matters, such as Oren Safdie’s “Private Jokes, Public Places.”

But this is perhaps just Joe talking, the native New Yorker who once worked with many urban planners.

 If/Then

Richard Rodgers Theater (226 W 46^th Street)

Music by Tom Kitt; book and lyrics by Brian Yorkey; directed by Michael Greif; choreography by Larry Keigwin; orchestration by Michael Starobin; music direction by Carmel Dean; sets by Mark Wendland; costumes by Emily Rebholz; lighting by Kenneth Posner; sound by Brian Ronan; hair and wig design by David Brian Brown; Cast: Idina Menzel (Elizabeth), LaChanze (Kate), Anthony Rapp (Lucas), Jerry Dixon (Stephen), Jenn Colella (Anne), Jason Tam (David), Tamika Lawrence (Elena) and James Snyder (Josh).

Running time: 2 hours, 50 minutes including one intermission

Tickets: $67-$142