During the 47 years that he ruled the island, Fidel Castro was a dominant and near-daily presence in the lives of ordinary Cubans. He cajoled, lectured, and admonished them, feuding with enemies -- especially the United States -- in looping, animated speeches that lasted hours. On television, on the radio and in the Communist Party newspaper Granma, he was always there, talking, talking, talking.

Raúl Castro is nothing like that.

Beyond the debate over whether the reforms enacted in recent years by the younger Castro -- who is 83 -- are meaningful or not, his style has brought an important shift that has done just as much as anything to dial down hostilities with Washington and set the stage for President Barack Obama's normalization announcement Wednesday.

That move will test a theory that has been popular for years in Democratic circles, and a few Republican ones, too.

The Castro government doesn't fear the embargo and interminable hostilities with the United States; it has thrived on them, so the thinking goes. What worries the island's control-minded leaders far more is change.

The response of Cuban officials to this argument has always been: Try us. But a new relationship with the country Fidel Castro used to call "the colossus of the North," and its wealth, influence and power, could put significant pressure on the communist government whose post-Castro future remains murky.

"In the medium and long term, this is a challenge for the Cuban system, because it undermines the climate of hostility that has long been used to justify the one-party state," said Arturo Lopez Levy, a former Cuban government intelligence analyst who is now an adjunct faculty member at New York University.

Since taking over after his brother fell ill in 2006 and nearly died of diverticulitis, Raúl Castro has treated Cuba's presidency as more of a burden than a calling. He gives only a few speeches a year, reading from written text and wasting no words. He does not stay up late into the night charming visiting diplomats or Hollywood celebrities. Cubans go weeks without seeing him at all.

He is a lifelong military man, not a natural politician. He was 26 years old in 1958 when his elder brother ordered him to open a second guerrilla "front" in the Sierra Madre mountains of eastern Cuba, and he has spent his entire life in the older Castro's shadow.

"In the end, Raúl Castro will be remembered not for the communist ideals that he espoused as a young man, but for having achieved a landmark agreement with the United States to re-establish relations," Lopez Levy said.

"Relations with the United States were central to Cuba long before its founding as a republic," he said, "but they have never been relations of dialogue or with respect for sovereignty, and Raúl has achieved that, which is something very important to Cuban nationalism."

In his address Wednesday on Cuban state television to inform the country of the deal with his lifelong foe, Castro's military style was on full display. He read from a 10-minute statement, seated at a desk in uniform, with the portraits of Cuban independence heroes in the background and a wood-paneled wall that looked like something out of a Nixon-era suburban family room.

"President Obama's decision deserves the respect and acknowledgment of our people," Castro said, as stunned Cubans looked on. "The progress made in our exchanges proves that it is possible to find solutions to many problems," Castro said. "As we have reiterated, we must learn the art of co-existing with our differences in a civilized manner."

Castro has said he will step down in 2018. His ailing older brother is 88 and virtually absent from public life. Miguel Diaz-Canel, the 54-year-old vice president who would be in line to replace him, remains very much in the shadow of the Castros and their circle of aging army generals.

The Cuban government has long defended its strict political and economic controls with the argument that the United States would use any opening as an opportunity to stir unrest. But if tensions with the United States ease, Cubans will increasingly look inward at the shortcomings of their anachronistic system and Soviet-style planned economy.

"I want to see who they blame now for the economic collapse and lack of freedoms that we have in Cuba," dissident activist Yoani Sanchez wrote on Twitter after the White House announcement.

The narrow market opening permitted by Raúl Castro over the past few years has already shattered many of the ideological underpinnings of his older brother's brand of socialism. Where private enterprise is allowed -- food service, repairs shops, hair salons -- Cubans flourish. In dingy state-run factories, they see stagnation and ruin.

His version of carefully managed change is guided by what Cubans have come to see as his catchphrase: "Without haste, but without pause."

Many Cubans -- especially the younger generation -- want a faster pace.

As part of the rapprochement, U.S. officials say Cuba has agreed to expand Web access on the island, which has one of the lowest Internet use rates in the world. That will bring additional challenges, as Cuban officials have long feared the type of Web-enabled activism of the Arab Spring, and its potent cocktail of social media, smartphones and frustrated young people.

Obama's moves on Wednesday were the type of breakthrough many of them hoped for after he won the presidency in 2008. Cubans knew he'd questioned the long-standing U.S. trade embargo and thought his message of "change" might include them.

The new president began to deliver in 2009, making it vastly easier for Cuban Americans to visit relatives on the island and send money. The island's Cold War overtime, it seemed, was finally winding down.

Then the government threw Alan Gross in jail and snapped the thaw back into ice.

Cuba was once again in control of the relationship and the pace of change.

Wednesday's announcement puts the weight back on Cuba and Raúl Castro. Aside from the prisoner swap and the symbolic importance of renewed diplomatic relations, the president's executive orders make clear that more substantial change to the relationship will come only if he continues to open its closed economy and political system.

"The normalization of diplomatic relations will offer an opportunity and a challenge to deepen and accelerate the reforms," said retired Cuban diplomat Carlos Alzugaray, reached in Havana. "Cuba will have to take advantage of the opportunity but guard against other effects that new investment may bring."

Senior U.S. officials said Wednesday that the move will not end the democracy-promoting USAID programs that Gross was working for at the time of his arrest in December 2009. Instead, they will operate from within a future U.S. Embassy in Havana, and the Cubans will be watching and almost certainly trying to thwart them.

But those programs could switch from what was essentially undercover political activity to more above-board American training and assistance programs for the emerging small-business sector permitted by Raúl Castro's reforms, said Cuba analyst Phil Peters. That would be a trust-builder, if the Cubans allow it.

Cuba has yet to permit its small businesses and worker-run private cooperatives to engage directly with foreign companies and import the technology and goods they need, Peters noted. "It would be problematic if Obama has opened a door to significant business engagement and Cuba doesn't accept," he said.

With nearly 80 percent of the economy under state control and key industries like tourism and retail largely operated by the military, the government stands to profit, too, of course, from more robust trade ties permitted by the Obama measures.

"For a government that denies economic freedom and property rights, it seems clear that the changes proposed will first benefit the state apparatus," said Jose Daniel Ferrer, leader of the Cuban Patriotic Union dissident group in Santiago, the island's second-largest city. "Only in the medium or long term will we know the effect on the Cuban people."