Counterfactualis Interruptus at Fort San Juan

Today Yahoo News reported an intriguing story with tantalizing counterfactual possibilities, only to leave them blowing in the wind.

Archaeologists in North Carolina have just uncovered remnants of a long lost Spanish fort, whose origins date back to the year 1567, some forty years before the first permanent British settlement at Jamestown.

The story goes on to note:

"The settlement around Fort San Juan was occupied for less than two years and it met arather bloody end — likely brought on by the Spaniards' botched bartering for food and their sexual transgressions with Native American women. But the short-lived fort's traces serve as a reminder of how different U.S. history might have been if Spain had been more successful in its early colonial campaigns."

Well, yes, it is such a reminder....But how would American history have been different?  No one expects such a teaser to be fully answered in such a short story.   But after asking the question, the report devotes no further attention to the "what if?" premise whatsoever.  

Of course, had the fort been successfully defended, and had a more substantial Spanish presence developed in the Northeast and Mid-Atlantic, any number of possibilities come to mind: a Catholic instead of Protestant North America.  Fierce clashes between the Spanish, Dutch, British, and French. An earlier independence movement against Spanish rule....

Please, Yahoo, tell us more!