To Boyer, Santo Domingo represented a chance not only to increase the territory of his tiny state, but to secure its future as a free nation — poor and despised, perhaps, but undeniably free. With the eastern half of the island in Spanish hands, Spain or any other power could gradually amass a huge army there until it was prepared to strike. If Haiti held all Hispaniola, it would be much harder to invade.
To Riego, on the other hand, Santo Domingo might as well have been the nameless “little patch of ground/That hath in it no profit but the name” fought over by Denmark and Poland in Hamlet. It was being contested entirely for reasons of national prestige — or rather, to extirpate national shame. Since he had come to power, Spain had conceded the loss of New Granada and La Plata, and the lion’s share of the remaining empire was now in the hands of the king’s brothers — at least one of whom was a known foe of constitutional government. With this added to the inevitable public backlash in parts of Spain from the abolition of the fueros, the popularity of Riego and his Constitutional Party had sharply diminished. If he was to have any hope of surviving the next election, at the very least he could not suffer the humiliation of defeat at the hands of such an enemy as Haiti.
So he sent another 20,000 men to Hispaniola. If these men, schooled in the Peninsular War, were more familiar with the realities of this sort of warfare than the Frenchmen who had followed the hapless Leclerc twenty years earlier, they were no more immune to yellow fever and malaria…
One of the few things that Simón Bolívar and Prince-Viceroy Carlos had in common was their attitude toward the peace between Gran Colombia and the Spanish Empire. Both had been pressured towards it by their own exhausted governments, and each man had acceded to it in the belief that time was on his side. Bolívar saw in the Viceroyalty little more than a halfhearted attempt to make Spanish rule bearable, and one that would surely fall victim either to the sloth and ineptitude of the old guard or the revolutionary fury of the people. Then the war could resume, and this time it would not end until all the Americas were free.
To Carlos, it was the government in Bogotá that was doomed. It was a coalition of the aggrieved and the power-hungry presided over by a Caesar without the legitimacy of a king. Only the fear of reconquista was holding it together, and that had already failed in Argentina. Let the republic fall apart as it must, and Spain could pick up the pieces at leisure. (It is important to remember that holding political views which were considered passé even in his own time did not make Carlos a fool. Nor, contrary to what Virreinatan state propaganda may claim, can he be considered a clerical aristist ahead of his time. To him, Bolívar was no Hero or Great Man, but a dismally successful traitor and bandit.)
And, ironically enough, in 1822 neither man was particularly inclined to go to war over Santo Domingo — but for opposite reasons. Bolívar was genuinely anguished by the position he was in, torn between his old comradeship with the Haitian people and his anger over the crushing of the Spanish rebels on Hispaniola by those same people. His many appeals to Boyer in their correspondence were met with refusal after refusal… Carlos, on the other hand, was sublimely indifferent to the matter. This was Riego’s war — let him and his precious Cortes fight it. If they succeeded, Spain would have regained a colony, but not one valuable enough to gain them any glory. If they failed, blame would fall precisely where it belonged.
So both of them waited until the end of the year, when a hotheaded young adventurer came out of nowhere and changed the game completely.
--Dennis Lincoln, A History of the Caribbean (Vol. 2)