MIAMI — Ahead of President Donald Trump’s expected visit to Miami on Friday to outline his new U.S.-Cuba policy, Sen. Amy Klobuchar is urging the Trump administration to continue “expanding, not retracting, engagement with Cuba.”

In a letter sent Monday to Secretary of State Rex Tillerson, Klobuchar and several other Democratic senators are making the case that the former Obama administration policies, beginning in December 2014, to normalize economic and diplomatic relations with the communist island nation has proven positive for the U.S. economy, especially U.S. agricultural exports, and for national security.

“We have already started to see the benefits of a new approach with Cuba,” writes Klobuchar in highlighting how airlines, hotels and cruise ship companies have tapped into the island’s growing tourism market.

She also said Cuba annually imports $1.9 billion of agricultural products, a potentially valuable market for U.S. exporters who currently sell only $300 million to Cuba.

“Isolating Cuba again would not just block opportunities for American businesses, it would also allow competitors like China and Brazil to expand their operations,” said Klobuchar, echoing the arguments of top U.S. agriculture businesses.

Cuba hardliners say Obama’s rapprochement to Cuba only benefited the Castro regime — not the Cuban people — because it did not force the communist Cuban government to improve its human rights records, hold free elections or allow free speech or free press in exchange for removing decades of diplomatic and economic barriers between the two countries. They also oppose any legislative effort to lift the longstanding U.S. embargo against Cuba.

Klobuchar and a bipartisan group of other lawmakers are pushing legislation known as the Freedom to Export to Cuba Act. It would repeal provisions of the five decades-old U.S. embargo, including restrictions on financing and requirements to get special licenses for any business dealings with Cuba. Only Congress can lift the embargo.

Klobuchar also said that “bilateral cooperation with Cuba is good for our national security,” noting that more than a dozen retired military officers wrote to National Security Adviser H.R. McMaster pressing for an expansion of U.S. relations with Cuba.

“If we fail to engage economically and politically, it is certain that China, Russia, and other entities whose interests are contrary to the United States’ will rush into the vacuum,” they wrote. “We have an opportunity now to shape and fill a strategic void.”

A group of House lawmakers made the same point in a letter to Trump on Monday. U.S. Reps. Tom Emmer, a Republican from Minnesota, and Rick Crawford, an Arkansas Republican, two outspoken proponents of boosting ties to Cuba, led seven lawmakers in writing a letter warning that that failing to engage the island nation would open the door for traditional U.S. adversaries like Russia and China “to fill the vacuum in our own backyard.”

“Allowing this to happen could have disastrous results for the security of the United States,” they wrote. “We urge you to prioritize U.S. national security and not return to a policy of isolation that will only serve to embolden adversarial foreign power in the region.”

A Morning Consult national poll released on Monday by Engage Cuba found that most Americans, including 6 in 10 Republicans, support U.S. policies to expanded travel and trade with Cuba. The poll found that 65 percent of American voters want to keep Obama’s policies in place, while just 18 percent oppose those policies. It also found that 64 percent of Republicans back the Obama policies compared to 22 percent that opposed them. Engage Cuba supports lifting the embargo and erasing travel restrictions.

In her letter to Tillerson, Klobuchar claims that “economic and political engagement has also been good for the people of Cuba,” saying that more than 500,000 Cubans are running their own small businesses and “thousands more are earning money from the growing travel industry.”

“American business leaders and farmers deserve a fair shot to compete in a market just 90 miles from our shores,” she wrote. “We urge you to build on the economic, political, and national security progress we have made thus far by expanding, not retracting, engagement with Cuba.”

POLITICO reported last week that Trump is expected to visit Miami on Friday to announce he will tighten some restrictions on those who travel to and do business with Cuba, fulfilling a campaign promise to reverse the historic changes begun by former President Barack Obama.

The specifics of Trump's executive action aren't yet clear, according to sources familiar with the administration's discussions. But it's expected to bear the stamp of two pro-embargo anti-Castro Miami Republican hardliners, U.S. Sen. Marco Rubio and U.S. Rep. Mario Diaz-Balart, who helped advise the White House and national security officials.

On Monday, White House spokesman Sean Spicer did not comment on what the president may or may not say about U.S.-Cuba policy.

“I will say that when we have an announcement on the President's schedule, we'll let you know,” he told reporters during his daily briefing. “But just stay tuned. We have a very busy week — an ambitious agenda this week.”