* Opposition leader says economic woes draining government
* Vows to keep publicizing vote dispute round Latin America
* He points to "internal war" in ruling Socialist Party
Venezuelan opposition leader Henrique Capriles says President Nicolas Maduro's government will "cave in" under the pressure of growing economic troubles, in-fighting and a belief by many Venezuelans that it stole the April election.
Capriles is still disputing the election, which he lost to Maduro by a narrower-than-expected 1.5 percentage points. But if, as expected, the fraud claims get nowhere in Venezuela's courts, Capriles says other forces may sink the successor to the late socialist leader Hugo Chavez.
"I think this government, in the current conditions of illegitimacy added to a deep economic crisis it's showing no intention of addressing, is going to cave in," Capriles, the governor of Miranda state, told Reuters.
"What does that mean? Well, all the mechanisms are in the constitution: referendum, new election, resignation. But ... don't ask me for ways out that are not in the constitution. Our fight is a peaceful one," he added in an interview in a rural zone of the state on Friday.
Post-election street protests backfired for Capriles when some people were killed in the chaos, allowing the government to attack him as a destabilizer and killer.
Now he and other opposition leaders seem to be banking on a steady deterioration in Maduro's popularity and power. One possibility for opponents is a recall referendum, allowed in the constitution three years into a presidency.
That tactic was used unsuccessfully against Chavez during his 14-year rule of the South American OPEC nation.
Some opponents, though, say Venezuela's economic problems - slowing growth, untamed inflation, product shortages and hard currency bottlenecks - may prove too much for Maduro even before they can push for a recall referendum.
"They have an internal war ... and that person (Cabello) wants to be president but knows it's impossible via a popular vote. The only way, and this explains his game, is that things implode, break up, and he gets there by non-democratic means," said Capriles, 40.
Some opinion polls show Capriles a few points ahead of Maduro should a presidential election be repeated - an unlikely prospect, however, given the election board's multiple pronouncements that the results stand, including after an audit.
"This is the only government that took over and did not go up in the polls," Capriles said. "There was no honeymoon. Look at all the countries in the Americas and the world, a government goes up some 10-15 points after taking over. Look at the opinion polls now, Maduro has an average of 40 percent."
Maduro says the post-election dispute has laid bare Capriles' non-democratic intentions, and officials vilify the opposition leader daily as a "fascist" and "murderer."
Maduro accused Santos, a conservative U.S. ally, of stabbing him in the back and fomenting plots from Colombia to murder him and topple his government in a coup.
In a reprise of the frequent diplomatic spats that his predecessor and mentor, Chavez, had with Colombia, Maduro withdrew an envoy to peace talks between the Colombian government and Marxist rebels and ordered a review of relations.
"By creating a fuss, they're trying to stop me visiting other nations and stop other presidents seeing me. I'm going to keep touring Latin America, the next visit is a surprise," Capriles said in the interview during a visit to San Francisco de Yare to inspect a home-building project.
"They're also trying to distract attention from the nation's grave problems by generating a situation of scandal and conflict, so economic problems, poverty, and shortages are knocked off the front pages."
Capriles, who wants to introduce a Brazil-style mix of free-market policies and strong welfare protection, mocked Maduro's plethora of accusations of plots from Colombia, the United States and within Venezuela.
"He says they're going to poison him, that they're going to infect him with something from somewhere - that sort of thing sounded fine from Chavez. When Chavez said it, it was amusing, we laughed, or believed him, but from this gentleman, please!"
While disputing the presidential vote result in the courts, Capriles hopes to turn municipal elections in December into a plebiscite on Maduro's rule.
Capriles faces possible legal action for the deaths of some nine people killed during opposition-led post-election protests.
"They're trying to criminalize dissent," he said, questioning whether the killings had anything to do with politics. "None of the deaths the government has spoken of are linked to politics. And in this country, 50 people die each day from violence, yet the government does nothing."
Reuters interviews with relatives and neighbors in one Caracas neighborhood where three people were killed indicated that two were shot from gangs shouting pro-opposition slogans, while a third was probably a victim of common crime.
Capriles took a relatively moderate line against Chavez during last year's presidential election campaign, which the incumbent won before dying of cancer five months later. But he has been consistently aggressive against Maduro.
In the interview, he called him "two-faced," "weak," "incompetent" and "infantile".
"I never thought someone who was foreign minister for six years could be so dumb handling international relations," he said, referring to both the Colombian controversy and Maduro's earlier fury at Peru for urging dialogue between Venezuela's government and opposition.