(CNN) Colorado's controversial "red flag" bill was signed into law by Democratic Gov. Jared Polis on Friday, with more than half of the state's counties declaring opposition to it and many sheriffs promising not to enforce it at all.
"This is a moment of progress," said Colorado House Majority Leader Alec Garnett, one of the legislation's four sponsors. "Today, we did something that was difficult and that is going to save lives."
Known as the "Extreme Risk Protection Order," the law will allow a family member, a roommate or law enforcement to petition a judge to temporarily seize a person's firearms if they are deemed a risk to themselves or others. Fourteen other states have passed similar legislation.
Still, the law now faces major hurdles, with a pro-gun lobby group promising to challenge it in court. Additionally, a growing number of sheriffs in the state have vowed to ignore the law when it takes effect next year, calling it unconstitutional.
Weld County Sheriff Steve Reams told CNN last month that he would rather be found in contempt of court and locked up in his own county jail than carry out a court order to seize a person's weapon.
At least 10 other sheriffs contacted by CNN are lining up behind Reams, saying they are prepared to go to jail rather than enforce a law they believe would violate a person's constitutional rights.
"How many judges are going to send all the sheriffs in Colorado who are standing up to this to jail?" wondered Teller County Sheriff Jason Mikesell, who is among the sheriffs willing to choose jail over enforcement.
Garnett said he wasn't concerned about sheriffs being locked up.
"What I'm going to lose sleep over is, if that's the choice that they make, and someone loses their life, someone in crisis goes on a shooting spree, (or) someone commits suicide" because a gun wasn't taken away, he said.
Already, 38 of Colorado's 64 counties have officially declared their opposition to the bill, and 35 of them have passed formal resolutions against the law. Many of the resolutions declare the jurisdictions to be Second Amendment "sanctuary" or "preservation" counties, and pledge not to allocate resources to enforcement of the law.
Colorado Attorney General Phil Weiser he is "confident that when and if the time comes, all law enforcement officials will follow the rule of law."
Reams insists he's not bluffing. So does Prowers County Sheriff Sam Zordel.
"I've already asked the coroner if he wanted to come over (to the jail) and get some training," he said, explaining that if he becomes an inmate, the coroner would be tasked with running the county jail.
Others took a more measured approach.
"I'm willing to go to my jail for it, the only exception would be a totally extreme case and most sheriffs would agree with that," said Park County Sheriff Tom McGraw.
The law is meant to be used only in the most extreme cases, but critics believe it will allow for guns to be taken based on a false accusation. A non-partisan analysis of the bill by Colorado's Legislative Council Staff predicted that the number of false red flag petitions would be minimal, and that the law would only be used 170 times per year.
California and Washington use similar red flag laws even less than that, though a similar law in Maryland is enforced six times more often than the Colorado estimate.
"Rocky Mountain Gun Owners is going to file a lawsuit against the red flag legislation before the end of the session," the lobby group's executive director, Dudley Brown, said. The legislative session ends May 3. Brown also said there could be a second lawsuit filed after the bill becomes law, but declined to provide more details.
Brown is also planning recall efforts of "at least 10" state lawmakers who supported the legislation. Two Colorado lawmakers were successfully recalled in 2013 after supporting controversial background check legislation and a restriction on magazine size.
The El Paso County Sheriff's office initially said the county would file a lawsuit when the legislation became law. The county now says it is still "in the brainstorming phase" of a potential lawsuit, according to county spokesman Matt Steiner.
According to the Giffords Law Center, which lobbies for tougher gun laws, there have not been any successful legal challenges of any similar state laws. There is, however, an ongoing complaint in an Illinois district court asking for an injunction, arguing that the law violates the Second and 14th amendments.
Assuming Colorado's law withstands a court challenge, defiant local sheriffs are on a legal collision course with the state. State law enforcement agencies like the Colorado State Patrol do "not have the authority to supersede local control," and seize the guns instead, according to Shelby Wieman, a spokeswoman for Gov. Polis.
Polis is confident that law enforcement will not ignore court orders to seize weapons, but if they do, it would be for the district courts or the state attorney general to resolve.
The declaration of a "sanctuary county" borrows the phrasing used by immigration advocates to describe jurisdictions where local law enforcement does not cooperate with federal immigration authorities, even when undocumented immigrants charged with crimes enter local jails.
If it's OK to ignore immigration laws, why can't Colorado counties ignore gun laws?
University of Denver law professor John Campbell said local law enforcement "can't choose not to enforce their state's law." But the enforcement of federal laws, such as immigration legislation, are voluntary for local authorities.
If a sheriff were to ignore a court order to seize a person's guns and they use them to hurt someone, Campbell believes the sheriff could be held liable. Law enforcement has immunity for genuine mistakes, but not for recklessness or blatantly ignoring their legal duty.
"Those are classic conditions to create liability even when people typically would enjoy immunity," he said.
While the legal obligation to enforce court-ordered gun seizures is different than enforcing immigration laws, Campbell said the outcomes can be the same -- someone getting hurt or killed.
In 2015, 31-year-old Kate Steinle was killed by an undocumented immigrant who was released from jail despite a request from federal Immigration and Customs Enforcement (ICE) to turn him over. A federal appeals court ruled last month that Steinle's parents cannot sue over San Francisco's "sanctuary" policy that allowed her killer to avoid deportation and walk free.
Garnett said sheriffs should enforce the new gun law, but wouldn't make a statement on enforcing immigration law.
"Immigration laws are primarily federal issues and I'm not going to get into that," he said.
Sheriff Reams acknowledged his risk of liability for ignoring a court-ordered gun seizure, but he's not worried.
"The person who commits a crime against another is truly the person responsible," he said, adding that if a person is mentally ill, he would use existing laws to detain them for treatment. "We still intend to deal with the person."