HAVANA, June 3 - Felicia de la Caridad Alvarez, a resident of Old Havana, knows a thing or two about survival.

The 64-year-old former hospital custodian, blind in one eye, suffers from hypertension and diabetes. She rarely enjoys running water or electricity. The food in her refrigerator has spoiled. Even her TV is broken, leaving her unable to discern who, exactly, is to blame for her woes.

Millions of Cubans face a similar plight. Cuba's already inefficient state-run economy - long plagued by shortages - has descended in recent months into a full-blown crisis in the wake of hardened sanctions and a fuel blockade by the administration of U.S. President Donald Trump.

But - despite Trump's prediction in early January that Cuba was "ready to fall" and despite severely rationed power, a crumbling health service and the decimation of its crucial tourism industry - Cubans keep on going and the government is still in charge.

In part, that rests on years of practice. Cuba's government has long taught people like Alvarez to "resistir," a central tenet of its nearly seven-decade-old communist revolution. "Resistir" is shorthand for overcoming hardship in the face of seemingly insurmountable adversity.

"In order to survive, I have to keep fighting," Alvarez said. "What choice do I have?"

So she lugs assorted plastic containers and pots of water every day from several blocks away, she scrounges food from a nearby church soup kitchen and she goes without refrigeration in the 21st century.

But the continued existence of the Cuban model also rests on citizens' worries about the consequences of public dissent.

Protesting, Alvarez said, is out of the question, for fear of government reprisal. That was a view shared by some two dozen Cubans interviewed by Reuters in recent weeks.

"They could take revenge on my kids," said Alvarez.

Rights groups and the U.S. have long critiqued Cuba's response to dissent as heavy-handed and repressive, while Cuba justifie...