SACRAMENTO, Calif. — One of America’s closest allies during the fighting in Indochina four decades ago, General Vang Pao, found himself facing the full weight of the American justice system yesterday as he was ordered held without bail on charges that he plotted to acquire weapons and mercenaries to overthrow the communist regime in Laos.

In a scene far removed from the jungles of Southeast Asia, the venerated Hmong leader shuffled into a federal courtroom here with leg shackles and waist chains clanging over his orange jumpsuit. Family members packed the gallery, while 2,000 or more of General Vang’s supporters rallied noisily on a plaza outside.

A defense attorney, John Balazs, warned that consigning General Vang, 77, to jail “might end up resulting in a death sentence” because of his medical history, including bypass surgery, diabetes, and a stroke. “In this country, the United States of America, punishment is supposed to come after the trial,” the lawyer said.

Mr. Balazs called the aging general “an honored war hero” who could not flee and was never one to shirk a fight.

Magistrate Edmund Brennan said defense lawyers were missing the point when they argued that General Vang posed no danger because of his age.

“It’s not that there’s any risk of him becoming a foot soldier,” the magistrate said. “It’s his organizational skills. … It’s his being a general.”

A prosecutor, Robert Twiss, noted that General Vang has traveled regularly to speak to Hmong groups across the country. “If you were to go on Google, General Vang Pao is everywhere,” the prosecutor said. “It’s not like he’s housebound.”

Mr. Balazs insisted that General Vang got caught up in “a sting operation “and could not have been part of any plot because he concluded several years ago that Laos could not be retaken by force. “He has consistently in the past number of years advocated peaceful solutions in Laos, not violence,” the attorney said. Magistrate Brennan seemed entirely unimpressed with the defense’s arguments. He read off a list of high-powered weapons the group was said to have been seeking, including mortars, stinger missiles, and cluster bombs. “They just don’t accept the Neutrality Act,” the magistrate said, referring to General Vang and the nine other men charged with violating a centuries-old law that bans unauthorized military expeditions. “It’s not up to private groups to decide which countries this nation will be at war with and which nations this country will be at peace with,” the magistrate said.

The crowd outside, carrying signs reading “Vang Pao is Innocent” and “Justice Not Entrapment,” seemed upset but not terribly surprised when word came that the general would not be released.

“I’m so disappointed. He is not a terrorist,” a registered nurse from Sacramento, Lao Thao, 37, said. “It is wrong that they put him in jail.”

A former United States attorney from Minnesota who is joining General Vang’s defense, Thomas Heffelfinger, urged the Hmong crowd to stay united for the legal battle ahead. “We are not giving up,” he said.

Mr. Balazs marveled at the dedication of the throngs who stood for hours in the blazing sun. “It is truly amazing,” he said. Some of the men were wore traditional Hmong pants and colorful cloth belts. Some of the young women sported tank tops from Abercrombie & Fitch.

While General Vang’s attorneys described him as “a man of peace,” his recent record is more complicated. In 2003, he traveled to Amsterdam for peace talks with Vietnamese communists who are closely aligned with the regime in Vientiane. When the talks were disclosed and the general proclaimed his intent to settle the long-standing fight with the Pathet Lao, many in his community reacted angrily.

“There was an implosion of support among his veterans. People’s jaws dropped,” a one-time Washington representative for the Hmong, Philip Smith, said in an interview. “His fund-raising plummeted to zero, and his son’s house was burned.”

The reception in Laos was about the same. Rather than embracing the offer, the authorities denounced General Vang as a war criminal.

Since that time, Mr. Smith said, the general has been trying to rebuild his credibility. After speaking to him last fall, the New Republic wrote that he had reversed his position on peace with Vientiane. “The U.S. has better rifles, better guns than the communists,” General Vang said. “If they give me the guns, I can conquer Laos in 2007. I still believe I can do it.” Prosecutors read the quote aloud in court yesterday.

Mr. Smith said he believes opportunists drew the general into an ill-planned venture that collided with America’s new sensitivity about terrorism. “It breaks my heart to see him in jail when who should be on trial is the senior leadership of the Pathet Lao, who committed war crimes against humanity,” the former adviser said.