Theater

Messing is fine but basically miscast in ‘Outside Mullingar’

Part of what makes romantic comedies so satisfying is that we know the mismatched, bickering pair will end up together. The fun is in watching them get there.

Except, that is, in John Patrick Shanley’s sluggish, sentimental “Outside Mullingar,” which isn’t much fun at all.

The potential lovebirds are appropriately inappropriate. Rosemary Muldoon (“Smash” star Debra Messing, in her Broadway debut) and Anthony Reilly (Brían F. O’Byrne, the original priest in Shanley’s “Doubt”) live on adjoining farms in the Irish countryside.

They’ve grown up near each other but barely speak because Anthony once pushed Rosemary down. Mind you, she was 13 and he was 6. Thirty years later, she still holds a grudge.

To make matters worse, Rosemary owns a tiny plot of land in front of the house Anthony shares with his widowed father, Tony (Peter Maloney). This complicates the men’s comings and goings, but Rosemary has no intention to sell.

You can see where this is headed, right? Fear not — the show gets there.

For inspiration, Shanley looked to his own Irish roots, which he’d never really explored before, and back to the romance of his screenplay for “Moonstruck.”

Yet “Outside Mullingar” can’t seem to decide if it’s a rom-com or a drama, and wastes too much time on exposition and badly paced, maudlin scenes.

The show spends more than an hour on meandering conversations in which the characters — who include Rosemary’s mother, Aoife (Dearbhla Molloy) — prattle on about the infamous right-of-way and the father and son’s prickly relationship.

When we finally do come to the courtship, the leads don’t quite gel.

The balding, unfussy-looking O’Byrne is perfect as the melancholy Anthony — a man who says “I don’t know how” when he’s asked why he can’t be happy. But he’s saddled with a last-minute reveal that’s so left-field, so inane that it almost ruins the character.

Messing gives a valiant try as the chain-smoking Rosemary — her Irish accent is good enough — and shines with the acerbic banter.

“That’s a two-man job,” Anthony says after she informs him she was out cutting her own turf.

“Or one woman,” Rosemary dryly answers.

But the bottom line is that Messing’s too gorgeous to have been cast as someone who’s stunned when told she’s beautiful. The role called for a more unassuming-looking character actress — say, a younger Edie Falco or Allison Janney.

Overall, it’s as if Shanley, director Doug Hughes and the Manhattan Theatre Club had been afraid to let this play be as small as it needs to be. Even the production overcompensates, with meticulous rotating sets by John Lee Beatty and elaborate water effects.

It’s never a good sign when you find yourself looking away from actors to watch falling rain.