BOSTON – In a dramatic opening statement, Judy Clarke, the lead defense lawyer for Dzhokhar Tsarnaev, quickly, almost suddenly, acknowledged what to many has seemed obvious — that her client had in fact set off the bombs that ripped through the 2013 Boston Marathon and killed three people.

"For the next several weeks, we're all going to come face to face with unbearable grief, loss and pain caused by a series of senseless, horribly misguided acts carried out by two brothers," she said, naming Tamerlan Tsarnaev, 26, who is dead, and his younger brother Dzhokhar, then 19.

"There is little that occurred," Clarke said, referring to the government's description of the bombings and the subsequent murder of an MIT police officer, a carjacking and a shootout in nearby Watertown, Mass., "that we dispute."

"It was him," she said bluntly of her client, who sat slouched in a chair at the defense table. She added later that Dzhokhar Tsarnaev had to take responsibility for actions that were "inexcusable."

But this admission was only a prologue to her real point — that Dzhokhar Tsarnaev was not the radical jihadi that his older brother was — and her ultimate goal, which is to persuade the jury to spare him the death penalty and sentence him to life in prison without parole.

The persuasive powers of Dzhokhar Tsarnaev's older brother dominated the first day of a heart-wrenching trial that is expected to last through June, but is dragging Boston and the country back to the scene of the worst terrorist attack on U.S. soil since Sept. 11, 2001.

The case laid out

In opening statements, prosecutors and defense attorneys laid out the case's core dispute: Whether, as the prosecution argued, the evidence shows that Dzhokhar Tsarnaev was an intellectually and emotionally committed "terrorist" bent on avenging U.S. military campaigns in the Muslim world, partly to help him reach "paradise" after his death. Or whether, as Clarke argued, her client was a fairly normal teenager, interested in girls and cars and spending time on Facebook, who was under the heavy sway of the older brother he loved and respected and that Tamerlan Tsarnaev was the real perpetrator and planner of the crimes.

For Clarke, her blunt, even surprising admission about her client's actions seemed aimed at taking off the table any real dispute about who was behind the bombings, which she plainly felt would be easily proved. It was also a way for her to build a rapport with the jury: By ceding so much so early, she was telegraphing to the jurors that she would not waste their time on matters not in dispute and that she was thus leveling with them.

Her strategy seemed to be that if she was frank with jurors at the outset, they might trust her as she builds her narrative of how her client came to commit terrible, tragic acts — that he was induced and cajoled by his brother and does not deserve to be sentenced to death.

For the defense, the relationship between the two brothers will be both a vital and tricky part of the case. One of the first rulings by Judge George A. O'Toole Jr. of U.S. District Court on Wednesday was to limit the degree to which they could bring up the defendant's older brother in this phase of the trial, which decides guilt or innocence.

While noting that "some evidence of the brothers' interactions will be inevitable," O'Toole said the issue of whether Dzhokhar Tsarnaev was "more or less culpable" than other participants is generally not relevant in the first phase of the trial before sentencing.

The government, which gave its opening statements first, focused on the impact of the attack. The assistant U.S. attorney, William Weinreb, described in graphic detail how the bombs had ripped the flesh off spectators at the marathon and sent body parts flying in the air. He described the precise way in which the shrapnel had torn into the three victims who died — Martin Richard, 8; Lingzi Lu, 23; and Krystle Campbell, 29 — as relatives of all three listened intently in the courtroom. And, he said, Dzhokhar Tsarnaev was a full and equal partner with Tamerlan Tsarnaev in their murderous spree.