There would have been two America's. USA and CSA.

They lost Vicksburg, which was much more important than Gettysburg.

Militarily, but Gettysburg was the beginning of the end and signaled a loss of faith in Robert E. Lee's ability to get the job done so that when Pemberton surrendered the next day, it was all but over. The fat lady was on deck and warming up her vocal chords...

@n00b: Well that's just the problem. Lee mistakenly thought that winning battles means winning wars. That's not necessarily true. If the Confederates won at Gettysburg they would not have been able to do much else with an exhausted army, and could not pull off a Sherman's march, even just inside Pennsylvania. The war would not have been significantly changed. The northern factions were still in the majority pro-war, the war-time economy was still full of resources and intact, and Lincoln's character determines that the war would have continued.

Furthermore, the Round tops were not part of Lee's plan. His plan followed Napoleon's Waterloo strategy: Napoleon, being once an artillery officer and thus beleiving strongly in cannon power, bombarded the center and sent in his elite troops right down the middle, but the underestimated enemy drove him back. Similarly, Lee bombarded Cemetary ridge with his inferior cannon power (and most of the shots missed, it being dark) and followed with a doomed Pickett's Charge.

Even in the unlikely event the South won, the government there was relatively ineffectual and the agrarian economy means expansion would be limited. Eventually the two sides would recombine or get stuck in another war, which the North would win.

The war would have been longer but the confederates would eventually lose

honestly the drama over how poor the Union's morale was is completely overrated, even with defeat at Gettysburg the Union would keep up the fight

@the.dibster - you are probably right that winning Gettysburg would only have drawn things out, but I think you're wrong about Lee thinking that winning battles equaled winning wars. I was always under the impression that the whole reason he made the incursion into Pennsylvania was to try to scare the bejesus out of the North by taking the war to them, the idea being if he won a big battle or two in Northern territory they might sue for peace. Now it's entirely possible (probably even likely) he misjudged the Union's resolve to keep the fight up, but we'll never really know because he didn't win. But the point is that heading north was a calculated move to try to end the war quickly with a psychological victory rather than a simple victory in battle.