"We anticipate a negative foreign reaction," says a State Department spokesman, adding President Bill Clinton will press on. Long stalled in Congress, the bill got White House support only after Cuban jets shot down two Cessnas in February, killing four Cuban-Americans. The US says the planes were in international airspace. Havana says they were in Cuban airspace.
Under the new law, Congress would have to approve any move to lift the embargo against Cuba, and individuals who "use or profit from confiscated Cuban property" would be categorically denied visas to the US. A central provision, long opposed by the administration, would allow Cuban Americans to sue, in US federal courts, firms doing business on their former land, now expropriated by Cuba.
International response has been virulent. Both Mexico and Canada, America's partners in the NAFTA, have substantial links with Cuba, and have not taken kindly to this show of muscle. Nor will the EU accept any US claim to extra-territorial powers.
Says Wayne Smith, Latin America specialist at the Centre for International Policy in Washington: "I wonder how the US government would have reacted had Cuban planes been overflying downtown Washington, coming close to the White House, and dropping leaflets?"
The biggest winners are the hardlineMiami-based anti-Castroites, led by the influential Cuban American National Foundation and its ambitious leader, Jorge Mas Canosa. A Miami entrepreneur, wheeler-dealer, and veteran of the failed 1961 Bay of Pigs invasion, he has gone public about his desire to become the Cuban president.
Till recently, the Foundation was out of favour and waning in influence. Indeed, Canosa, Lt Col Oliver North's buddy and supporter of his illegal pipeline to the Nicaraguan Contras, is reported to have written the bill to toughen the embargo. The Foundation is big business, funneling money to political committees to help elect friendly politicians to Capitol Hill.
Though Clinton had pushed predecessor George Bush into tightening the embargo before the 1992 polls, of late he had been softening. Last year, he upset three decades of US policy by ending automatic political asylum for fleeing Cubans. This stripped Brothers to the Rescue, to whom the two planes belonged, of its humanitarian mission of helping rafters in the Florida Straits, and prompted the group to more overt anti-Castro activities.
So far, polls show massive support for Clinton's tough response. In fact, he might get Florida back for the Democrats. Another group of winners are giants in the hotel and the food and beverage industries who were being squeezed out of Cuba as Canadian, Spanish, Mexican and other firms rushed into the liberalised economy.
Cuba specialists say Castro remains firmly in power, with the army's full support. Cuba's incipient economic recovery, due to large-scale foreign investment and a flower-ing of small enterprises, has begun to replace the old despair with optimism. At a time when the failure of US sanctions is more apparent than ever, Congress, and an optionless White House, is lashing out at Castro's muscle-flexing by codifying into law a policy that is likely to do more harm to legitimate US interests than to Castro.