WASHINGTON (Reuters) - President Barack Obama said on Thursday that fighting drug abuse demanded a broad public health effort to curb demand for narcotics, but repeated his opposition to outright decriminalization.

“I am not in favor of legalization,” Obama told an event hosted on the YouTube website. “I am a strong believer that we have to think more about drugs as a public health problem,” he said, when quizzed by the online audience.

A long-standing push in California to legalize marijuana suffered a setback in November when voters rejected a ballot measure that would have lifted its prohibition by 54 percent to 46 percent.

The issue was highly popular among online questioners and Obama said it was “entirely legitimate” to debate if the U.S. war on drugs was working.

Citing the success of U.S. public health campaigns against cigarette smoking, drunk driving and to promote the use of car seat belts, Obama said the country had made “huge strides” over the last 30 years by targeting popular attitudes.

“On drugs, I think a lot of times we’ve been so focused on arrests, incarceration, interdiction, that we don’t spend as much time thinking about how do we shrink demand,” he said.

“In some cities, for example, it may take six months for you to get into a drug treatment program. Well, if you are trying to kick a habit and somebody says to you, come back in six months, that’s pretty discouraging.”

He said it was worth looking at the allocation of resources between law enforcement and health programs, but vowed not to let up on traffickers.

“We have to go after drug cartels that not only are selling drugs, but are creating havoc, for example, along the U.S.-Mexican border,” he said.

U.S. efforts to stem the illegal drug trade, first called the “War on Drugs” by President Richard Nixon in 1971, rely on policies to discourage output, distribution and consumption. They involve participation of a number of foreign countries.