NEW YORK – Cesar Sayoc, the Florida drifter who mailed 16 crudely improvised explosive packages to critics of President Donald Trump, was sentenced to 20 years in federal prison Monday for a domestic terrorism spree that sparked a nationwide scare last year.

Manhattan U.S. District Court Judge Jed Rakoff said Sayoc, 57, mailed the pipe bombs intending "to strike fear and terror into the minds of their victims and to intimidate

those victims — mostly prominent political figures — from

exercising their freedom."

Although the bombs did not explode, and no one was injured, the judge said: "The nature and circumstances of the ...offenses are, by any measure, horrendous."

Sayoc created "a climate of fear and terror, going on, day after day, for several weeks," Rakoff added.

The packages targeted former President Barack Obama, former Vice President Joe Biden, former Secretary of State Hillary Clinton, actor-director Robert De Niro, cable TV network CNN and others. The mailings prompted nationwide alerts at post offices, as well as work and personal locations of potential targets.

The sentence spared Sayoc from the term of life imprisonment recommended by prosecutors and federal sentencing guidelines but doubled the 10-year minimum sentence urged by federal defenders.

Sayoc, who wept openly while the sentence was imposed, minutes earlier tried to hold back tears while saying he regretted his actions.

"I am beyond so very sorry for what I did," Sayoc told the judge.

He outlined a life he said was marred by his father's desertion from the family, learning disabilities, sexual abuse by a Catholic priest while in prep school, drug and steroid abuse and depression. But the circumstances didn't excuse his actions, he acknowledged.

"Your Honor, I understand now that I have committed a serious crime. I fully accept responsibility," he told the judge.

Referring to his intended targets, he added: "I will be apologizing to them for the rest of my life."

In urging a tougher penalty, federal prosecutors cited Sayoc's planning of the spree, his continued bomb mailings after the first devices were discovered, his arrest history, and what they said was his failure to fully accept responsibility and express remorse prior to sentencing.

"This was not a whim or reaction in one moment in time," said Assistant U.S. Attorney Jane Kim after noting that Sayoc started researching bombmaking in 2016, roughly two years before the mailings.

Federal defenders assigned to represent the virtually penniless defendant argued that the minimum sentence would give Sayoc hope that he would not die behind bars. They argued that the steroid abuse that clouded his judgment started when he was a scrawny kid trying to bulk up and spiraled out of control when Sayoc worked as a former bodybuilder. exotic dancer, club bouncer, and disk jockey.

The defense team also argued in a sentencing memo that Sayoc "found life" in Trump's self-help books and presidential campaign. The longtime Florida resident became radicalized by right-wing media rhetoric that, amid the biological effects of steroids, convinced him that Democrats who criticized Trump were enemies, the defense team contended.

"We believe that the President's rhetoric contributed to Mr. Sayoc's behavior in this offense," Federal Defender Ian Amelkin added as he addressed the judge.

Rakoff brushed away that argument, saying "correlation and causation are two very different issues." Instead, the judge focused on whether Sayoc intended to harm or kill his intended targets.

An FBI laboratory report on the devices found they were packed with fireworks powder, swimming pool chemicals, and broken glass. However, the fusing system "lacked the proper components and assembly" to initiate an explosion.

"It cannot be determined if the non-functional fusing system is the result of poor design or the intent of the builder," the report said.

Sayoc and his defense team conceded prosecution arguments that there was some chance that the devices could have detonated. But they insisted there was never any intent to cause harm.

The judge said he accepted that view.

"I conclude in the end that Mr. Sayoc, though no firearms expert, was fully capable of

concocting pipe bombs capable of exploding," said Rakoff. "His decision to instead design the pipe bombs so they would not likely explode was, in the court's view, a conscious choice" — and one that should be considered in sentencing.

"He hated his victims, he wished them no good, but he was not so lost as to wish them dead, at least not by his own hand," added Rakoff.

The nerve-jangling bomb threats erupted in October when suspicious packages began arriving in U.S. Postal Service facilities and at the offices or homes of Sayoc's targets.

He mailed the devices from southern Florida, the area where he lived in a white van festooned with stickers and photos that boosted Trump and criticized prominent Democrats and other opponents of the political leader he came to idolize.

The mailings prompted safety concerns for postal workers, first responders and Trump critics. The packages left the nation on edge because they were mailed within days of three other hate crimes, including the fatal shootings of 11 at a Pittsburgh synagogue.

Authorities captured Sayoc in Plantation, Florida, on Oct. 26, 2018. They tracked him down through evidence from FBI laboratory tests that linked him to 11 of the 16 packages.

Sayoc pleaded guilty in March to an indictment that eliminated the mandatory life sentence he could have received under the initial charges prosecutors filed against him — use of a weapon of mass destruction.

Referring to the devices as he confessed, Sayoc said he "was aware of the risk they could explode" and cause injuries or property damage.

For his prior court appearances, Sayoc was dressed in dark blue prison scrubs. Following the judge's intervention, Sayoc appeared in court for sentencing wearing a grayish blue plaid jacket, white shirt, and a light gold tie. His hands were free, but his legs were shackled at the ankles.

His mother, Madeline Sayoc, and one of his sisters were in the courtroom for sentencing. Showing little outward emotion, they sat near psychiatric experts who said the confessed mail bomber would likely not commit violent crimes now that his steroid usage has been forcibly halted.

Rakoff said he would recommend that Sayoc serve his sentence at a federal prison in Florida, near his family. However, he said the formal decision would be made by the Federal Bureau of Prisons.

Follow USA TODAY reporter Kevin McCoy on Twitter: @kmccoynyc