There's a foamy meniscus in an imperial pint that divides bitters from pale ales. Terry Foster, AHA style book author, points to the dissipation of that line during the more than 300-year evolution of the drink. The comparison of bitter vs. pale is often owed to little more than which side of the Atlantic a brewer calls home. Though, at times of fluctuating commercial popularity, the pale style stands with solid body, head & hopping; never adulterated with spiking agents like porter, nor degraded with adjuncts as Pilsener in America.
Semantics aside, there's magic in brewing an IPA. Through its time in my cellar, I'm tempted daily to go ahead & tap that beautiful brew, anxious to taste the bitter quotient of hops but curious to let time expand the malt's flavor. I imagine that sailing crews of long ago felt the same urge, save the fact that their Eastern-world destination was their target drinking date, and not a fast-dwindling rotation of other brews getting shared quickly in my home kegerator. The current trend is really a Renaissance: some forget that IPAs experienced early popularity in America's early centuries.
The arrival of each case of India Pale in the new world was just as anticipated as the sight of a cellared keg is to today's American homebrewer. Though many brewers cite the IPA as their launching point for the craft, a gateway brew it is rarely called! As the nitro stout was to Britain, the weakening of emigrated German lagers to "True American" status has set the American IPA in a particular class. Even amongst pale ales, examples often wear the moniker as hyper-hopped versions of pale ales, quickly rushed to store shelves instead of laying in wait for luscious caramel malt flavors to match the powerful citrus hop punch of a true IPA.
America's IPA's flourish along the Hudson, Mississippi & Willamette rivers as their continental parent brews flourished along the Thames. Within each region, a brew for any local meal. Hoppy West Coast pales bite back at Alaskan King Crab. Sweet Amarillo's dance around spicy gumbo in New Orleans. Tremendous, zesty New York pizza slices get soaked in a full-bodied Centennial punch. Whether it's from cask or keg there's a nation of dishes to be tabled aside a glass brimming with historic solidarity. An American IPA is the most authentic recipe for the classic seafaring style. A great recipe has a few pounds more malt than a standard pale & broad laces of different caramel malts calculated in ratio to what can seem like infinite IBU's. Enough of these three components will feed well a clean Chico yeast from a starter, and test the patience of the homebrewer.
My advice: find or devise a solid recipe, keep plenty of hops with varieties starting with a 'C', use good brewing practices & read some good regional cookbooks from across the country while you await the goods. For fun, be like the hip Minnesota bar patrons & mix different American IPA's until you find the perfect 'hoptail'!