By Pascal Fletcher
CARACAS (Reuters) - When Venezuelan President Hugo Chavez was briefly deposed in a 2002 coup, it was Cuban leader Fidel Castro who roused foreign ambassadors to lobby for his return and helped organize his rescue by loyal troops.
Nearly a decade later, the Cuban "Comandante", now 84, has rushed to the aid again of the Venezuelan socialist soul mate 30 years his junior. It was Castro who persuaded Chavez to undergo tests that led to the detection and removal of a cancerous tumor.
"I give thanks to Fidel Castro ... he's practically been my top doctor," Chavez, 56, told supporters outside his palace in Caracas this week after flying back from Cuba to scotch rumors that his health woes might have loosened his leadership grip.
Castro, Cuba's iconic leader for nearly half a century who was laid low by intestinal illness in 2006 and later ceded the reins of power to his brother, has loomed larger than anyone else in Chavez's month-long treatment and convalescence in Havana.
The episode gives another glimpse into the personal and ideological symbiosis between two of the world's most charismatic but divisive politicians, left-wing populists who have turned baiting the United States into lifetime careers.
According to Chavez's own account, Castro personally gave him the news about the existence of the cancer requiring immediate surgery.
As photos and videos of the duo in tracksuits chatting together were drip fed by both governments as proof of Chavez's recovery, the Venezuelan leader revealed Castro was also watching like a doting relative over his exercise and diet, sending him treats like peanut butter, lamb and tilapia fish.
Writing in his published online "Reflections", Castro modestly rebuffed Chavez's thanks as "too generous", while hailing their "close and indestructible friendship".
"We're happy to see them together, master and disciple," read one admiring post commenting on Castro's words.
With the practiced eye of a veteran sports coach picking out a new prodigy, Castro first rolled out the red carpet in 1994 for the little-known ex-paratrooper and coup-plotter fresh out of a Venezuelan jail. Since then, the relationship has blossomed into a potent political partnership.
Mentor, father figure, instructor -- all these words have been used to describe the Svengali-like influence that the veteran Cuban revolutionary has apparently wrought over his younger consort who has ruled Venezuela since 1999.
From slogans to strategies and policies, Fidel Castro has passed on to Chavez the anti-capitalist toolkit, including the not so subtle arts of daily mass propaganda and such survival tips as how to dodge assassination plots and coup bids.
It is no accident that the Venezuelan paratroopers wearing black facepaint who paraded this week at their country's 200th independence anniversary celebrations, bawled out in time to the quick step "We are socialists, anti-imperialists", whereas a few years back, the cry was the more neutral "parachutists".
The combination of a politicized armed forces loyal to a charismatic supreme leader with a dominant governing party led by the same person is just one aspect of the changed Venezuelan political landscape that mirrors features of Cuba's system.
Critics, including Washington, also point to persecution of political foes, politicization of the judiciary and other state institutions, and sweeping economic nationalizations as other borrowings from Havana that reflect the Castro-Chavez relationship.
There is no doubt the two men share a personal chemistry.
They have celebrated birthdays together in Havana and Caracas, played baseball together, toured jungle beauty spots and exchanged hours of conversation in live phone and television hookups broadcast in both nations.
Chavez reverently calls his friend "Fidel, the giant".
Castro, more measured and reflecting the apparent hierarchy of the master-disciple relationship, calls him "Chavez".
The Venezuelan has been a willing pupil, gifted with even more bombastic rhetorical stamina than veteran orator Fidel.
Their partnership has impacted both nations, and, to a lesser extent, the wider hemisphere and world.
The gnarled vine of Cuba's revolution, its economic lifeblood staunched by the collapse of the Soviet Union -- its longtime benefactor -- and drained by mismanagement and U.S. sanctions, has drawn fresh sap from the alliance with Chavez.
South America's biggest oil producer, Venezuela sends Cuba oil on preferential terms.
Chavez's government has adopted from Cuba's well-thumbed communist manual national health, literacy and food programs, leftist economic policies, neighborhood political committees and militias, and carefully choreographed government events.
At the same time, thousands of Cubans have poured into Venezuela.
Under cooperation accords, they have worked as doctors, teachers, sports instructors, security and defense advisers and even aerobics teachers in the slums, many drawing paychecks from Venezuela's energy ministry, the national cashbox.
Critics of Chavez have pilloried what they call a giving away of Venezuela's sovereignty, and its oil, in the alliance.
They scornfully refer to a new twin-nation entity, "Venecuba" even though Venezuela's constitution, unlike Cuba's, still guarantees multi-party politics and a free press.
In Latin America, Chavez, eagerly assuming Fidel Castro's revolutionary mantle, has made some progress in grouping like-minded leaders who share anti-U.S. and anti-capitalist views in his Bolivarian Alliance for the Americas (ALBA), cemented as much by preferential Venezuelan oil supplies as by ideology.
Wider afield, Chavez's overtures to Iran and Russia have rung alarm bells in Washington and Europe over arms purchases, intelligence sharing and nuclear technology transfer, even as Venezuela remains one of the biggest U.S. oil suppliers.
But while the aging Fidel Castro was able to hand on the baton of Cuba's presidency in 2008 to his younger brother Raul, his veteran defense minister, Chavez's health scare revealed the absence of a clear successor in Chavista ranks.
That is a potential vulnerability as a presidential election approaches in 2012.
"Chavez lacks a legitimate inheritor, a Raul Castro," wrote Cuban-born Venezuelan commentator Fausto Maso, as speculation swirls about how effectively Chavez can now rule while he receives cancer treatment.
(Editing by Andrew Cawthorne and Kieran Murray)