With six and a half weeks to go before the start of the first trial in the Oregon standoff case, nine of the 26 defendants have pleaded guilty to a federal conspiracy charge.

Three of the nine were part of leader Ammon Bundy's inner circle. Two of those have negotiated, or are in the process of negotiating, a resolution to a federal indictment in Nevada as well.

The developments are not unusual in a complex conspiracy prosecution involving multiple defendants, but they likely "ratchet up the pressure'' on those defendants still holding out, legal observers say.

"This is proceeding in a very typical fashion,'' criminal defense lawyer Kevin Sali said.

At least 95 percent of federal criminal prosecutions end in guilty pleas, said Tung Yin, a professor at Lewis & Clark Law School. So for roughly a third of the defendants indicted in the 41-day armed takeover of the Malheur National Wildlife Refuge to have accepted plea deals isn't surprising, he said.

Defendants have to weigh the risks of going to trial and the potential prison sentences they could face if convicted, against any government plea offer, which often leads to reduced charges and less time behind bars in exchange for a quicker resolution of the case and acceptance of responsibility.

There's also the likelihood that the government will reward certain defendants with lighter sentences if they agree to share information about the underlying conspiracy or testify against the alleged leaders. In federal conspiracy cases, the government often tries to indict enough people in hopes that less-culpable defendants will flip and testify against those at the top rung, criminal justice experts say.

"It's not uncommon for the last ones standing to be the biggest figures,'' Sali said.

For seven of the defendants, the stakes are much greater because they're under federal indictment in both in Oregon and Nevada.

The federal prosecution in Nevada, which stems from an armed standoff with federal officers near the Bundy Ranch in Bunkerville in 2014, involves more serious allegations with the potential for substantial prison time.

Those charges include conspiracy to commit an offense against the United States, conspiracy to impede or injure a federal officer, using and carrying a firearm in relation to a crime of violence, assault on a federal officer, threatening a federal law enforcement officer, obstruction of the administration of justice, interference with interstate commerce by extortion, and interstate travel in aid of extortion. If convicted of each count, defendants could face a maximum of 96 years in custody. Convictions on the four counts alone of carrying or use of a firearm in the course of a crime of violence could bring more than 80 years in prison should each count relate to a separate incident.

Ryan Payne and Blaine Cooper, two of the seven defendants facing prosecution in Oregon and Nevada, have moved in the last month to resolve both cases at once, accepting plea deals that will substantially reduce their time behind bars. Payne is expected to face a total of 12 years in prison; Cooper, six years.

The remaining five defendants "are probably all fishing for something like that,'' Yin said.

Steven Wax, who served as Oregon's federal public defender for 31 years before retiring in 2014 and now is legal director of Oregon's Innocence Project, said when he represented defendants who faced prosecutions in two different jurisdictions, his goal was to achieve a global resolution.

"There's a reasonable likelihood you'll continue to see more people pleading guilty as the trial date approaches,'' Wax said.

Though the Oregon refuge case is, so far, playing out much like other federal multi-defendant prosecutions, it's anything but a typical conspiracy case.

It isn't a whodunit mystery or the more common drug-trafficking conspiracy.

Here, the alleged offenses occurred in the public spotlight, with vast media attention and daily news conferences at the Harney County refuge, and defendants using social media to document their actions and demands.

What particularly sets it apart is the strident ideological stance of the defendants.

Ammon Bundy and his brother Ryan Bundy, for example, conceded in court papers this week that they were leaders of the 41-day refuge occupation and that they intended to stake a claim to the federal wildlife sanctuary through what's called adverse possession. They believe they were exercising their constitutional and statutory rights to lay claim to the federal property in protest of what they consider the federal government's overreach in control of public land.

So far, the Bundys and their co-defendants have lost most of their pretrial court battles -- from efforts to suppress private Facebook messages and accounts, to demands that prosecutors turn over the federal investigation into alleged misconduct by FBI agents at the scene of the shooting of occupation spokesman Robert "LaVoy" Finicum. They also lost an appeal challenging the simultaneous federal prosecutions in two states.

Their only major victory came from the court's dismissal of one count in the indictment -- possession of firearms in the course of a crime of violence -- that would have brought a mandatory minimum sentence of five years in prison, and a maximum sentence of life. The sentence also would have to be served consecutively to any others imposed on other counts.

Ammon Bundy and Ryan Bundy this week were denied pretrial release after a three-hour hearing, in which Ammon Bundy's lawyer made the head-spinning decision to put him on the witness stand.

Under cross examination by Assistant U.S. Attorney Ethan Knight, Ammon Bundy admitted he stayed at the refuge, that he and others changed the signs and obtained a postal address to receive mail there, that he knew federal employees worked there but were not present when he and supporters arrived, and that the actions taken at the refuge resulted from "more of a combined effort."

His statements, plus his attorney's acknowledgement that the Bundys and others controlled access to and from the refuge and that many were armed, help establish the elements needed for a conviction on the charge of conspiring to impede federal officers at the refuge through intimidation, threats or force.

"It's almost a universally bad idea to have your client making public statements before your trial," Sali said. "I would tell you it's a very unusual move. You're doing something very risky for the slight possibility of winning release with less than two months before trial.''

Wax added, "It is most unusual for that to happen, and it is a risky proposition.''

Why? Because the statements can be used as evidence. A transcript of Tuesday's hearing likely was ordered, and prosecutors undoubtedly will reference it so that they can use Ammon Bundy's own words against him at trial, legal observers said.

It's possible his lawyer concluded there was little Ammon Bundy could lose at this point, Yin said. Further, it was U.S. District Judge Robert E. Jones who asked during the detention hearing whether Ammon Bundy was going to speak because, he said, based on what he'd heard from Bundy's lawyer and read in his motion, all he knew thus far was that "he's a good guy."

After that, lawyer Marcus Mumford, after briefly conferring with his client, called Ammon Bundy to the stand.

Other defense lawyers said they can't remember having seen a defendant take the witness stand in a detention hearing. Defendants, like Ryan Bundy, sometimes read statements to the judge but don't take the stand.

"I would certainly hope if that kind of momentous decision was made it was not a spur of the moment thing,'' Sali said.

As things stand now, eight defendants have been granted the right to delay their trials. That leaves Ammon Bundy, Ryan Bundy, Joseph O'Shaugnessy, Peter Santilli, Kenneth Medenbach, Shawna Cox, David Fry, Jeff Banta and Neil Wampler, who are set to go to trial Sept. 7.

As the trial looms, each defendant will try to minimize his exposure.

Yin called the Bundys' adverse possession defense a "creative" argument that might not fly at trial. Judge Jones already dismissed it when he ordered the Bundys to remain in custody pending trial. "To me, it looks like a plea would be the best option but it's a little bit harder for the person in the situation to make that decision. It's not the defense lawyer who is going to prison, if convicted," Yin said.

Defense lawyers say they've seen defendants make those calculations differently. There are defendants who consider the pros and cons of going forward to trial, based on a full analysis of the government's evidence, and the exposure of prison time if convicted versus a potential plea; principled defendants who understand the risks and consequences but are adamant they're not guilty and steadfast about fighting the charges; and those who, despite overwhelming evidence against them, may have other goals of simply getting their day in court to argue their case.

"This crime is not your typical crime to the extent there seem to have been political motivations for some or all involved to do what they did,'' Wax said. "They may want the opportunity to tell their story to a jury.''

Three of the defendants, for example, have chosen to represent themselves.

Despite what seems like voluminous evidence against the defendants, the Bundys and others may want to go to the "common people,'' and hope that a jury, or even one juror, will challenge the government's case through jury nullification, said Andrew Chongseh Kim, an associate professor at Concordia University School of Law. That occurs when a jury in effect nullifies a law that it believes is wrongly applied to a defendant, despite its belief that a defendant is guilty of the violation charged.

"It seems highly likely the prosecution is going to be able to prove every single element of the crime easily, but maybe the Bundys believe they still have a chance to be acquitted because of jury nullification, that a jury, or even single juror may prevent prosecution as a democratic check against the tyranny of the government,'' Kim said.

"If someone really wants to use the system as a way to get his message out,'' Sali said, they might disregard the risks and "let the chips fall as they may."

-- Maxine Bernstein

mbernstein@oregonian.com

503-221-8212

@maxoregonian