NEW YORK — For the last 37 years, Belmont Park has been where horse racing’s grandest dreams have gone to die.

Since Affirmed won the Triple Crown in 1978, 13 horses have had a chance to complete the sport’s greatest trifecta by winning the Belmont Stakes.

A few – Silver Charm, Real Quiet, Smarty Jones – came tantalizingly close. One of the strongest favorites, Big Brown in 2008, delivered perhaps the worst performance, pulling up before he reached the finish line. I’ll Have Another never made it to the starting gate in 2012.

None could overcome Belmont Park’s array of challenges, from the 11/2-mile distance to the crop of fresh horses who line up to pick off a Triple Crown aspirant.

Now American Pharoah will take his shot after a brilliant win over the mud in the Preakness. Here are five key storylines as Saturday’s race approaches:

• Is American Pharoah the horse to break the Triple Crown drought?

Many analysts sense he might be the one, for several reasons.

First is the colt’s talent. Pegged as the best in his crop last fall, he’s the rare horse who has held that distinction through prep season and the first two legs of the Triple Crown.

Most of the contenders he’ll face at Belmont Park were beaten in the Kentucky Derby, and American Pharoah did it easily despite running less than his best race. The only two horses who seriously challenged him –Firing Line and Dortmund – will sit this leg out.

The Belmont tends to favor horses who run close to the lead, which is American Pharoah’s favored spot.

• Which challenger seems best poised to knock him off?

It’s easy to forget now, but this year’s Derby field was regarded as the best and deepest in decades. Beyond Firing Line and Dortmund, the list of perceived threats to American Pharoah included the Todd Pletcher-trained duo of Materiality and Carpe Diem, and Wood Memorial winner Frosted.

All three skipped the Preakness and are expected to be fresh for a return bout.

Materiality finished sixth in the Derby and he might be a horse on the rise after he didn’t race as a 2-year-old.

Carpe Diem went off as the third choice in the Derby, and despite a disappointing performance there, Pletcher has speculated that he might fare better over a longer distance.

Frosted is a tough, versatile horse with dangerous closing speed.

• Can a fresh shooter follow the same path Tonalist did last year?

Tonalist took the “fresh horse” debate to another level when he beat California Chrome after running in neither the Derby nor the Preakness. This angered California Chrome co-owner Steve Coburn enough that he called Tonalist’s connections cowardly.

Don’t expect to hear a similar diatribe from trainer Bob Baffert if American Pharoah loses. But a similar storyline is possible given the presence of the Pletcher-trained Madefromlucky. Just like Tonalist, he skipped the Derby and Preakness and instead won the Peter Pan Stakes at Belmont Park.

• Will the jockeys play an outsized role in determining the winner?

Because 3-year-old thoroughbreds aren’t used to running 11/2 miles, the Belmont often presents a unique test of nerve and judgment for their riders.

The race hasn’t gone well for favorites who have waited too long to stalk the lead. But it also has proved disastrous for those who have moved too soon.

• If American Pharoah wins, will he lift the entire sport?

A Triple Crown would make the California-based colt one of the biggest equine stars in recent memory.

But would he captivate a new generation of fans to a sport that has suffered decades-long declines in attendance, betting handles, breeding stock and mainstream interest? Industry analysts say that’s a lot to ask from one horse, no matter how strong the initial interest in his accomplishment.