An effort to harshly tighten restrictions on Cuban Americans’ travel and remittances to Cuba has come down to last-ditch negotiations in Congress over a huge government spending bill.

It remains unclear exactly how the restrictions would be tightened if a rider attached by Rep. Mario Diaz-Balart to the spending bill is approved by Congress, as members of Congress and news reports are predicting.

Congressional aides say travel and remittances would be returned to the level set by President George W. Bush in 2008: only one trip every three years for “family reunifications,” a cap on remittances of $1,200 per year and a tighter definition of “family.” Other analysts of sanctions on Cuba say travel and remittances would return to the slightly easier Clinton-era level, which allowed one trip per year and more cash assistance.

But it was clear that Diaz-Balart’s rider was worrying supporters of President Barack Obama’s decision in 2009 to lift virtually all restrictions on Cuban American travel and remittances to the island.

“My concern is that this [measure] is very much alive,” said Rep. José E. Serrano, a New York Democrat who has fought for years to relax or abolish all U.S. sanctions on the Cuban government.

“Some Democrats backing the administration policy [on Cuba travel] seemed resigned to defeat,” noted an Associated Press story on the closed-door negotiations over the massive compromise spending bill.

Some Democrats in the House and Senate don’t want to be seen favoring increased travel to Cuba at a time when Havana has been cracking down on dissidents and is holding U.S. government contractor Alan Gross in prison, said a Republican senator’s aide.

“Alan Gross and beatings of dissidents make it difficult for the average member of Congress to endorse gestures to Cuba,” said the staffer, who asked for anonymity because he wasn’t authorized to comment on the issue.

Gross is serving a 15-year sentence on charges of violating Cuba’s national security laws by delivering a satellite telephone to members of the island’s Jewish community so they could have better access to the Internet.

Diaz-Balart’s rider must survive the tough negotiations between the Republican-controlled House and Democratic-controlled Senate, expected to be concluded before the end of the year.

Obama also has threatened to veto any rollback of his Cuba policies.

Some of the more controversial riders on the spending bill already had been dropped by Tuesday as the negotiations moved forward. But Senate Majority Leader Harry Reid said Tuesday that “some major issues [remain] to be resolved, some foreign policy issues, including Cuba.”

White House Press Secretary Jay Carney said there remains “issues to be resolved with the spending bill,” including “attempts to attach riders on our foreign policy goals, the environment and other areas.”

Diaz-Balart’s measure was approved by a House committee this summer as a rider to a Treasury spending bill that was later rolled with eight other spending bills into the one massive measure now under negotiation.

Legal travel to the island by Cuban Americans exploded after Obama lifted the restrictions in 2009, although many Cuban Americans had been going to the island illegally through third countries.

Miami attorney Aidil Oscariz said the Diaz-Balart move “is against my constitutional rights to travel, rights to association and it violates very basic human rights. I have a real problem with it.”

Oscariz, 35, said she was born in Cuba and moved to Miami when she was 3 years old. She has returned nine or 10 times to visit aunts and a now-deceased uncle.

But during the Bush administration, the aunts and uncles did not fall into the definition of family, and she could not visit. Since Obama took office, she has been back twice.

“I was hoping to go soon. I guess I better go right away,” Oscariz noted. “Changing [the regulations] back would be cruel. It’s not fair to Cubans: No other people are told what family members they can visit.”

Passengers on legal direct flights from U.S. to Cuban airports rose by 60 percent from 2009 to 2010, said Armando Garcia, president of the Miami-based Marazul travel agency.

Diaz Balart’s measure, Garcia added, “is going to have a devastating impact on this community. This is going to bring back cruelty.”

Vivian Mannerud, founder and president of Airline Brokers, which also charters flights to the island, added that the Diaz Balart rider would cost the South Florida economy millions of dollars in lost travel industry jobs and fees collected in Miami.

Tightening the restrictions will only force Cuban Americans to travel illegally through third countries, she added, pumping more money directly into the coffers of the Cuban-government-controlled Havanatour agency.

Under the Obama administration, Cuban Americans can currently travel to the island and send as much money to relatives as they wish. Some have been going there once a month and more to take care of sick relatives.

Ironically, the Diaz-Balart rider would have no impact on the number of non-Cuban Americans traveling to the island because such “people to people” trips are covered by a different section of the U.S. sanctions on Cuba. “They are going to limit Cuban American travel, and what happens to the people-to-people travel?” said Teo Babun, who runs a nonprofit that organizes humanitarian visits to Cuba. “They’d be letting Americans go but not Cubans?”

Miami Herald staff writer Frances Robles and Washington Bureau reporter Erika Bolstad contributed to this report.