WASHINGTON: When Curtis Reeves shot to death a fellow movie spectator who threw popcorn at him, the police veteran reignited a heated debate in the United States over when self-protection is a legitimate defense.

The January 2014 altercation took place in Florida, where lawmakers this week debated whether to further extend immunity granted under the state's "Stand Your Ground" law to people who committed involuntary manslaughter when they felt threatened.

Reeves has invoked the controversial law -- which helped neighborhood watcher George Zimmerman get acquitted over the shooting death of teenager Trayvon Martin in a move that triggered nationwide outrage.

Florida, under Republican rule, is said to have the most gun permits of any US state. It is also the third most populous.

The Sunshine State was the first to adopt a "Stand Your Ground" law, in 2005, with the blessing of the arms lobby.

Under the measure, defendants can use force without retreating if they feel they are in immediate or imminent threat of bodily harm or death.

More than 20 states followed Florida in adopting similar legislation, triggering many more self-defense claims in homicide cases.

The laws have proven citizens innocent after they were brutally and inadvertently plunged into violence. But they have also been exploited by drug traffickers and murderers to escape well-founded charges.

- 'Anecdotal' benefits -

"Although there may be anecdotal evidence of this incident defused or that tragedy avoided by 'Stand Your Ground' approaches, overall, 'Stand Your Ground' laws do not deter burglaries, robberies, or aggravated assaults," said Chuck MacLean, associate professor of law at Indiana Tech Law School.

The laws, on the contrary, "increase overall homicides, firearm homicides and firearm accidents," he told AFP.

Since it passed the law in 2005, Florida has seen a 24 percent increase in homicides, according to a study published in January in the Journal of the American Medical Association.

Another report by the National Bureau of Economic Research in 2012 found that "Stand Your Ground" laws were strongly associated with homicides among white males.

"Given that the overwhelming majority of concealed guns are owned and carried by white males in the United States, it is plausible to expect the SYG impact to be more pronounced for this group," the study said.

"Furthermore, it has been argued that the SYG laws may embolden individuals to stand their ground rather than simply walk away and may lead to individuals resorting to the use of deadly weapons even in incidents with no real threat to people's lives."

- Popcorn against gun -

Reeves failed to convince a Tampa judge that his act fell under the measure.

In her ruling last week, Circuit Judge Susan Barthle said she had "considerable doubts about his credibility," and the septuagenarian is now sure to face trial.

The ex-police officer's testimony was "significantly at odds" with that of other witnesses and with the physical evidence, according to the judge.

A surveillance camera recorded part of the incident inside the darkened movie theater.

As commercials are shown on the silver screen, Reeves can be seen leaning toward his neighbor seated in the row in front of him, upset that the man is tapping away on his smartphone.

The neighbor, 43-year-old Chad Oulson, is seated next to his wife and texting instructions to the babysitter watching their 22-month-old daughter.

The argument between the two men becomes heated, and Oulson throws his popcorn bag toward Reeves, who then draws his gun and fatally shoots Oulson in the chest.

Defendants in Florida must be able to prove that they reasonably believed they were in imminent danger of grave bodily harm or death before pulling the trigger.

Republican lawmakers have proposed a bill where that burden would fall to the prosecutor, who would need to prove "beyond a reasonable doubt" that the defendant's claim to self-defense is baseless. -AFP