The San Francisco public defender will argue that an African American man charged with battery and resisting arrest in connection with a scuffle with BART officers had every right to fight police — a legal strategy that comes amid heightened scrutiny over police use of force and issues of race.

Videos of the July confrontation that were posted on social media showed one of the officers apparently punching a handcuffed Michael Smith, 22, whom police had detained in response to reports of an armed man trying to rob someone on a BART train. Prosecutors say the videos tell an incomplete story and that body cameras worn by police show that Smith was kicking and spitting at BART officers.

Jury selection is scheduled to begin Friday in Smith’s trial on six counts of battery on a police officer and one count of resisting arrest. Public Defender Jeff Adachi, who will represent Smith personally, said he will make what amounts to an argument of self-defense.

“His actions were necessary in order for him to save his life,” Adachi said. “This was a situation where the officers really made assumptions about him and acted too swiftly.”

The incident happened just before 1 p.m. on July 29 as BART officers responded to the Embarcadero Station to reports that an armed man was trying to rob a passenger on a train.

Adachi said Smith hadn’t tried to rob anyone. The 911 call was made in response to a dispute that Smith and his pregnant girlfriend had with a passenger as they were on their way to a doctor’s appointment, the public defender said.

Police found no weapon on Smith, and prosecutors charged him only with crimes that stemmed from the confrontation on the station platform with the BART officers.

Lawyers for both sides agree that as the train pulled into the station, officers with guns drawn ordered Smith and his girlfriend onto the platform. What happened next will be up to the jury to decide.

Prosecutors contend that Smith defied officers’ orders, forcing police to use a “controlled takedown” to detain a man they suspected was armed with a gun.

Footage from the officers’ body cameras, which has yet to be shown publicly, shows Smith “bite, kick, finger-gouge and spit” on the officers, said Alex Bastian, a spokesman for District Attorney George Gascón.

The cell phone footage that circulated on social media was fuzzy and shot at a distance. The officers’ cameras gave a more complete picture of the incident, Bastian said.

“We were even able to see the defendant kicking the body camera off the chest of one of the officers,” he said.

Adachi, however, said any violence was instigated by police.

“What you see is the officers have him at gunpoint and then they immediately sweep his feet and slam him on the ground,” he said. “Mr. Smith is detained, yet they continue to use force. Even after they search him, they continue to use too much force.”

Smith has been arrested by BART police on two other occasions, in 2013 on suspicion of petty theft and in 2014 for alleged fare evasion. Both times he resisted officers, and in one case he tried to take an officer’s gun, BART officials said.

Adachi will argue to the jury that the officers’ actions in this incident were unreasonable or excessive. He cited a provision in the law that allows a defendant to “lawfully use reasonable force to defend himself” if officers use excessive force.

Some legal experts said it might be difficult to persuade a jury that an accused batterer of police was acting in self-defense.

“Jurors tend to assume that the cops are telling the truth,” said Hadar Aviram, a law professor at UC Hastings in San Francisco. She said publicized video footage of police beatings may be reducing juror skepticism, but “when it’s the cop’s word against the citizen’s word, it’s pretty difficult.”

Another potential barrier is that the judge would instruct jurors to consider the situation from the perspective of a reasonable, objective observer in Smith’s position, said Robert Weisberg, a Stanford University criminal law professor and co-director of the school’s Criminal Justice Center.

“You could make the argument (for a reasonable fear of excessive force), but it would be very, very hard,” Weisberg said. Defense attorneys seldom attempt it in court, he said.

Adachi said the trial will “really focus on how police are trained. After the Oscar Grant case, there was a huge effort to reform BART, yet what we see here is officers working to escalate a situation.”

Grant, who was also 22, was shot dead by a BART police officer while lying facedown on the Fruitvale Station platform after a fight erupted on a train in the early morning hours of New Year’s Day 2009. Johannes Mehserle, who shot Grant, was sentenced to two years in prison after being convicted of involuntary manslaughter.

The case has been followed by a wave of national scrutiny over police killings of unarmed black men, many of which have been filmed and posted to social media.

Smith, Adachi will argue, was victimized by police and now faces “very serious” criminal charges. “They’re throwing the book at him,” he said.

Chronicle staff writer Bob Egelko contributed to this report.

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky