Last week, Portland resident Leah-Lynn Plante spent the first of what could be more than 500 nights in prison for refusing to testify before a federal grand jury about people she might know who might have been involved with the political vandalism in Seattle on May Day.

That's a lot of nights for a couple of mights.

Plante has not been charged with a crime. In fact, the court granted her immunity, meaning she could not invoke her Fifth Amendment right against self-incrimination. Lawyers for two other grand-jury resisters—Matt Duran and Katherine Olejnik—have argued that the jury's questions about their acquaintances and housemates violate the First and Fourth Amendments. The court has decided that their silence is not protected by the First, Fourth, or Fifth Amendments.

But if Plante, Duran, and Olejnik continue to remain silent, they could be imprisoned until the expiration of this grand jury. Grand jury hearings are secret, but during Plante's open contempt-of-court hearing, Judge Richard A. Jones said they could be incarcerated until March of 2014.

At Plante's hearing, around 40 supporters and activists—mostly dressed in black—sat in the federal courtroom while extra security, from the US Marshals and the Department of Homeland Security, stood by. As federal marshals prepared to take her away, Judge Jones reminded Plante that "you hold the keys to your freedom" and that she could be released at any time if she chose to "exercise your right to provide testimony."

It was an odd turn of phrase—the same judge who, that morning, legally blocked her from exercising her right to remain silent was sending her to federal detention for not exercising a "right." The 40 or so supporters in the courtroom stood solemnly as she was led away. "I love you," Plante said to the crowd as marshals escorted her through a back door. "We love you!" some people in the crowd said. The lawmen looked tense for a moment, their eyes bright and their jaws clenched, ready for action. Then everyone walked out quietly, without incident.

The only federal defendant to be sentenced for a May Day–related crime so far—damaging a door of a federal courthouse during the smashup—was arrested in early May and sentenced, in mid-June, to time served.

Which brings up a pointed question: Why was the only federally identified May Day vandal sentenced to time served (about a month), while people granted immunity from prosecution—Plante says government attorneys don't dispute that she wasn't even in Seattle on May Day—are looking down the barrel of 18 months in federal custody? Why is a person who might know something about a crime, but who steadfastly insists she has her right to remain silent, facing more severe punishment (about 18 times more severe) than the person who was sentenced for actually committing that crime?

Minutes before Plante's hearing, her attorney, Peter Mair sat, brow furrowed, in the courthouse lobby. Mair worked for years as a federal prosecutor—he's indicted the Speaker of the House of Representatives, has prosecuted mobsters, and is familiar with how grand juries work.

But given the way government attorneys are using grand juries now, he said, "you could indict a ham sandwich. Defense attorneys are not allowed in, other witnesses are not allowed in... They're going to send this poor girl off to prison for a year and a half. And the great irony is that the one guy who pleaded guilty to the crime served—what? Forty days?"

He reiterated what many other lawyers in the course of this story have argued—that the grand jury system was originally included in the Bill of Rights to avoid frivolous government indictments. But, he said, federal prosecutors have been using that system as a tool for investigation and intimidation since the Nixon administration: "They used it to chase dissidents."

Jenn Kaplan, an attorney who represented Olejnik, also showed up at Plante's hearing because she was "curious" to see how it would pan out. "Theoretically, the grand jury serves an important function as a jury of peers to find probable cause," she said, "instead of the US Attorney using it to indict anyone at will without having to publicly demonstrate why to anybody."

The system has become, she said, "a constitutional bypass around the Fourth and Fifth Amendments, allowing the government access to evidence they wouldn't otherwise have." It is also a useful tool to intimidate people, she said, creating a chilling effect on political activism. If simply knowing someone who might be suspected of political vandalism puts you at risk of a subpoena and 18 months in jail, it gives you a strong disincentive to associate with such people. She also cited an article in a Northwestern University law journal about the history of grand juries that states:

The fundamental principles of free association and political freedom under the First Amendment, coupled with the historic right against self-incrimination codified in the Fifth Amendment, establish a "political right of silence." This right should bar the government from compelling cooperation with the grand jury under threat of imprisonment in an investigation involving political beliefs, activities, and associations.

In the end, Kaplan said, it is "far too drastic to bring someone before a grand jury" just because that someone might know someone who might have committed an act of vandalism.

Once Plante had been led away, her supporters walked out of the courtroom. A few looked a little teary. Then they milled around the elevators and on the front lawn of the courthouse, talking about going somewhere to get some food and maybe a drink. One mentioned an FBI special agent who, before the final hearing started, had spoken with her and some of her friends while they waited in the antechamber. I saw him at the end of their conversation, crouching on the carpet while the rest sat on a bench. As I approached, she was quietly asking him: "How do you feel about the way the warrants were executed? People hog-tied in their underwear?" Perhaps sensing new ears listening to the conversation, the agent stood up, walked away, and leaned against a wall until the courtroom opened.

In the end, the quietly tense saga between activists, lawyers, judges, and cops was a symphony of incongruity. Nearly everyone involved seemed to believe they were doing the right thing and executing their duty to their larger community. It was a collision course of ideals: Nobody was there for fun, or for greed, or for anything so simple as selfishness.

The guards at the security check to the courthouse—which activists and I shuffled through several times, emptying our pockets, taking off our shoes, putting our bags through the scanner—said that day didn't seem particularly busy. "You should see Thursdays," one said. "Bankruptcy hearings." Those days, he said, were jammed with people.

"How long have those bankruptcy days been so busy?" I asked.

"Oh, you know," he said. "For three or four years—since the big crash. Lot of people hurting from that. Lot of people hurting."

The day after Plante was sent to prison, activists in Portland organized a "grand jury resisters solidarity march," during which they smashed out the windows of four banks: Chase, Umpqua, US Bank, and Wells Fargo.