Rev. Al Sharpton defended himself Tuesday against the release of a 19-year-old videotape depicting a conversation about a cocaine shipment between him and a government agent posing as a drug dealer.

Sharpton said the tape, secretly recorded and then used against the civil rights activist, was being released now because people want to see his political career ruined. But, he said, if anything it will only rally people around him.

"It's a cheap smear campaign, but I think it will end up generating sympathy for what I have been fighting for all these years against government abuses in trying to bring down successful minority businesspeople," Sharpton said during a news conference in Harlem on Tuesday.

"It will take more than a distorted, 19-year-old tape to stop my exploration to run for the president of the United States," he said.

In the 1983 tape, which was to be aired on HBO's Real Sports With Bryant Gumbel on Tuesday night, Sharpton, with his trademark bushy hair and an unlit cigarette in his mouth, is seen talking with self-described mobster Michael Franzese and FBI agent Victor Quintana, who was posing as a South American drug lord. The three were discussing promoting boxing matches and musical events.

The conversation turned to drugs.

Sharpton asks the undercover agent, "What kind of time limit are we dealing with?"

"Coke?" the agent asks.

"Yeah." Sharpton says.

The phony drug dealer says, "Could be about the same time we have $4 million coming to us."

Sharpton: "End of April?"

"End of April. Six weeks from now. Is that a good time you think?" the agent asks.

"Probably," Sharpton replies.

Later on, the undercover agent offers Sharpton a finder's fee for help with the drug deal and says to Sharpton, "I can get pure coke for about $35,000 a kilo ... Every kilogram we bring in, $3,500 to you. How does that sound?"

Sharpton nods.

On Tuesday, Sharpton said the recording was all part of a government set-up and he was just playing along with the man that he thought was the drug kingpin because he was afraid the man might be armed.

"The guy had come to me. In the middle of conversation he started talking about how he could cut me in on a cocaine deal. I didn't know what this guy was on about. I didn't know if he was armed. I was scared so I just nodded my head to everything he said and then he left," he said. 

No charges were ever brought against Sharpton because of the tape, which was allegedly made to get Sharpton to act as an informant for the feds into an investigation into corruption by Don King and the boxing industry.

Sharpton admitted in 1988 that he informed for the government in order "to get rid of drugs and election fraud" in black neighborhoods.

He denied informing on civil rights leaders and organized crime figures.

When HBO reporter Bernard Goldberg confronted Sharpton with the tape during the interview set to air Tuesday night, Sharpton stormed out of the room. He later came back to attack the tape and defend himself.

Sharpton also accused the cable network of selectively airing damning sections of the tape, and threatened to sue HBO if it failed to air the whole videotape.

Fox News' Rick Folbaum and the Associated Press contributed to this report.