Tourists take pictures Tuesday in Havana. (Reuters)

As President Trump’s national security team worked over the past several weeks on a promised new Cuba policy designed to roll back the Obama administration’s diplomatic and economic openings to the island, a steady stream of lawmakers, business leaders and Cuba experts rushed to offer guidance to the White House.

With few exceptions, their advice was: Don’t do it.

Farm state Republicans have appealed to Trump to help them expand Cuban markets rather than close them. A newly introduced Senate bill to lift remaining travel restrictions has attracted 54 co-sponsors, including 10 Republicans. The U.S. Chamber of Commerce and National Association of Manufacturers have called for expanding relations with the island. Major travel and agricultural companies and associations have publicly warned that a reversal would cost American jobs.

U.S. and international human rights organizations, while condemning ongoing Cuban government repression, say that tightening the screws will only bolster government hard-liners, putting even more pressure on the island’s nascent civil society and private sector.

The Commerce and Treasury departments, which administer many Cuba regulations regarding travel and commercial activity, have explained the difficulty of a rollback after two years of business expansion and contracts. Trump’s agriculture secretary, Sonny Perdue, told Congress last month he favored opening U.S. credit markets for Cuban agricultural imports, barred by U.S. law.

On Friday, Trump plans to travel to Miami to announce a decision that senior administration officials said as recently as Wednesday had not yet been finalized. According to the Miami Herald, his speech will be delivered at the Manuel Artime Theater in Little Havana, a highly symbolic venue named after a leader of the Bay of Pigs exile invasion of Cuba in 1961, a failed U.S.-backed attempt to overthrow the revolutionary government of Fidel Castro.

Trump’s rhetoric will probably be “very, very tough,” said Mark Feierstein, the senior director for Western Hemisphere affairs in former president Barack Obama’s National Security Council, who helped implement the December 2014 Obama opening that Trump has called a “bad deal.”

But the administration’s changes are likely to leave in place the basic components of the Obama opening — diplomatic relations, along with conditioned trade and travel — while tightening each in ways that will complicate but not undo them, according to senior administration officials and several people who have lobbied them from Capitol Hill and the U.S. business community, all of whom spoke on the condition of anonymity about the emerging policy.

The U.S. Embassy in Havana is expected to remain open but will continue without an ambassador. Existing restrictions on business dealings with the Cuban government, and especially its economically powerful military, will be made more legally explicit, and at least some planned expansions of commercial activity will be frozen.

Some restrictions on American travel may be reimposed, along with limits on how often Cuban Americans can travel and send money.

“We are supportive of continued economic development, as long as it is done in full compliance with our existing statutes not to provide financial support to the regime,” Secretary of State Rex Tillerson told Congress on Tuesday.

“The general approach,” Tillerson said, “is to allow as much of this continued commercial and engagement activity to go on as possible, because we do see the sunny side” of “benefits to the Cuban people.”

The main supporters of an extensive reversal have been Cuban Americans in Congress, led by Sen. Marco Rubio (R-Fla.), and Rep. Mario Diaz-Balart (R-Fla.), both of whom are expected to be with Trump in Miami. Rubio, a onetime presidential candidate who clashed repeatedly with Trump during the campaign, was noticeably helpful to the White House during last week’s Senate Intelligence Committee testimony by former FBI director James B. Comey.

After a long line of questions about Trump’s private conversations with Comey, Rubio quickly changed the subject to the problem of leaks to the media.

In an interview this week with TV Martí, the U.S. government-funded broadcaster to Cuba, Diaz-Balart said he was sure Trump would announce “a real change” in relations. The Cuban government headed by Raúl Castro, the late Fidel Castro’s brother, he said, “is a narco-terrorist tyranny, and we know President Trump understands this.”

The government in Havana has remained quiet about the possible changes, although a high-ranking Cuban official told CNN this week that Raúl Castro is willing to negotiate a new deal with Trump.

At the core of the Cuba policy debate is a clash over the most effective way to hasten a transition to democracy on the island.

Obama argued that five decades of U.S. trade sanctions had failed to achieve that goal or dislodge the Castros from power. By normalizing relations and facilitating trade and travel between Americans and Cubans, he asserted, the United States would spread democratic ideals on the island, while American diplomats could nudge the government toward greater openness in a post-Castro era.

The results have been uneven. Cuba’s authoritarian one-party system remains largely unchanged, and dissidents say government repression has increased over the past two years.

Jose Daniel Ferrer, leader of the Patriotic Union of Cuba (UNPACU), the island’s largest dissident group, called this month in a letter to Trump for “maximum reversal of some policies that only benefit the Castro regime.”

But supporters of engagement say it’s unrealistic to expect liberal democracy to bloom in two years, especially with the larger U.S. trade embargo still in force. The strategy needs more time, they argue, and policymakers should trust in the power of markets and free information to deliver desired change.

Cuban authorities have acceded to some American conditions, including allowing a dramatic expansion of Internet access on the island that has shattered the information monopoly once enjoyed by Cuba’s state-run media.

An increase in tourism and hotel construction has been one of the few bright spots in the Cuban economy. The number of U.S. visitors who are non-Cuban American increased by 74 percent in 2016, facilitated by the restoration of commercial flights between the two countries.

Among more than 4 million visitors last year, a record, 615,000 came from the United States, more than half of them Cuban Americans.

More than a quarter of the Cuban labor force no longer works for the communist government, from software programmers to nail salon owners, private taxi drivers and restaurant owners. Those Cubans would take a direct hit from a policy reversal.

“More than half my customers are Americans . . . the best tippers,” said Dionys Diaz, 33, waiting for tourists outside Havana’s iconic Hotel Nacional in a pink 1954 Chevy convertible.

Diaz and his relatives — including a brother-in-law in Florida — had pooled their money to buy the vehicle and restore it, and he charges tourists $25 for rides along the Malecon esplanade.

Any reversal of the opening could backfire politically, said Carlos Alzugaray, a retired Cuban diplomat in Havana, who favors U.S. engagement. “The hard-liners are going to have a field day.”

A major rollback, he said, “would take us back to the idea that if you punish the Cuban people, they will overthrow the government, and that’s not going to happen.”

Miroff reported from Havana.

Correction: An earlier version of this story misidentified former Obama administration official Mark Feierstein. He helped implement the Obama policy, but did not help negotiate it.