The late 1700s the island saw a change for the worse as the Haitians began to revolt (1791) and many of the wealthy landowners in the east, including in Santo Domingo, fled the island. This revolt, primarily between the slaves in the French section of the island (Haiti) and the wealthy French landowners and France, led to Spain attempting to seize the entire island. This move failed though and in 1795 France took control of the entire island, including what is today the Dominican Republic.
Under French rule consistency was lacking. First the slaves were freed, then the government clamped down and allowed few freedoms, and finally the people revolted and the Haitians declared independence, while destroying many cities in the eastern half of the island. Then the Spanish residents on the island's eastern half rose up against the French and in 1808 overthrew the French and took Santo Domingo, with some assistance from the British, ending French rule and placing the eastern half of the island back under Spanish rule.
The Spanish showed little interest in their returned colony as the land became somewhat chaotic and ungoverned. In 1821 the region declared independence as Spanish Haiti, but this only provoked the nation of Haiti to invade and take the entire island. Under Haitian rule, the culture of the ethnic Spanish was suppressed as the language, dress, religion, and many customs were suppressed or outlawed. It also ended slavery on the island and represented a major shift in power from primarily white Spaniards to primarily black slave descendants.
In 1844 the people on the eastern half of the island revolted and gained independence from Haiti. During the first decade or so after declaring independence the people of the east fought the Haitians, while the government continuously used these battles as excuses to gain more and more power, essentially creating a dictatorship. However this power also led to regular coups and elections, which continuously shifted power from person to person.
After these disastrous battles and power struggles, the people requested and received annexation from Spain, again making them a colony of their former master in 1861. However, this temporary peace was marred by those who now wanted independence and wars again continued as rebels fled to Haiti in order to resupply and prepare. However, these rebels were isolated from each other and when together never seemed to agree, so it seems like a failed effort until 1865 when Spain restored the country's independence.
After independence the country was in ruins and there was no cohesiveness in the political realm. From this point until the early 1900s the country suffered coup after coup and military battles throughout the country. However, the country also began to gain revenues from sugarcane production and many sugarcane producers in the region struggled due to their own domestic affairs. This industry helped the country as it demanded better roads, ports, communication, and infrastructure.
With growth also came increasing debts though and soon numerous foreign countries were demanding repayment. In 1905 the United States guaranteed the debts would be repaid, but in exchange the U.S. government received over half of the Dominican Republic's customs duties income. This didn't settle domestic arguments and political chaos as the country was struck by battle after battle. Due to this and the agreement the country had with the United States, the U.S. entered in 1916 to restore order. This order was resented by the people and in 1922 the U.S. withdrew from the country.
In 1924 the country was taken over by Rafael Leonidas Trujillo, who gained nearly the entire vote through threats, bribes, and intimidation. Trujillo established a strong handed dictatorship based on economic growth. He also thought highly of himself as every success was credited to him. He also took over private enterprises and personally controlled over 50% of the economy by the 1950s. His rule finally ended in 1961 when he was assassinated.
From Trujillo's death until 1965 the country again broke down into chaos. This led to the request for U.S. assistance and the U.S. again came in and controlled the country for nearly two years. This operation helped foreign nationals escape, while waiting out the ensuing civil war.
From 1966 until the late 1980s the country's political stability slowly leveled off as power was shifted from party to party, however the economy also shifted dramatically and took some severe downswings, preventing sustainable progress. The political situation deteriorated in 1990s when the elections were said to have been rigged, an event that again occurred in 1994.
In 1996 the Dominican Republic's political situation finally stabilized as elections have truly been free, however this again hasn't improved the economy as much of the country remains impoverished the currency can't seem to remain stable.