In a Jan. 7 town hall event, President Obama bristled at the suggestion that he has a plan to confiscate Americans' guns. (CNN)

Ahead of President Obama’s town-hall-style event on guns Thursday night at George Mason University, the campus police chief sent an email to students alerting them that protesters might show up outside the venue with their firearms.

He noted that Virginia is an open-carry state, in which it is legal to publicly carry and display licensed firearms. Though it is not clear whether anyone did, the matter-of-fact tone of the notice underscored the challenge for a president who has described his inability to move the nation toward what he considers ­“common-sense” restrictions on firearms as his most frustrating failure.

And it may have highlighted the scope of Obama’s disconnect with a large segment of the American public on the issue.

As the president appeared before a audience of 100 partisans on both sides of the debate at George Mason — and was beamed into the living rooms of homes in red and blue states on the live CNN broadcast — his efforts to bridge the cultural divide on guns looked increasingly hopeless.

“Celebrate that we’re good people and 99.9 percent of us aren’t going to kill anyone,” Taya Kyle, the widow of former Navy SEAL Chris Kyle, whose story, including his death at the hands of a mentally unstable man, was the basis of the movie “American Sniper,” told Obama plaintively. She had written a commentary article earlier in the day saying stricter gun control “won’t protect us.”

President Obama formally announced a set of executive orders on gun control on Jan.5. Here is what you need to know about how the regulations tighten gun sales and expand background checks. (Claritza Jimenez/The Washington Post)

Obama thanked her and her husband for their “service.”

The president has ventured into a battle in which specific policy proposals are overshadowed by deeply held attitudes about the proper role of the federal government. The debate is taking place in a country where nearly a third of the citizens live in a home with guns, according to federal statistics, and 22 percent report owning firearms.

“I respect the Second Amendment. I respect the right to bear arms,” Obama told moderator ­Anderson Cooper on Thursday night. “But all of us can agree to take common-sense steps to keep guns out of the hands of people who want to do harm.”

Aides said before the event that the president was eager for a “serious conversation” with his opponents. But Obama’s frustration was palpable from the start. “Our position is consistently mischaracterized,” he said. Noting that the National Rifle Association had declined an invitation to the town hall, the president said: “I’m happy to meet with them. . . . But the conversation has to be based on facts and the truth and what we are proposing, not some imaginary fiction that Obama is trying to take away your guns.”

The event came as the capstone to a week in which Obama announced new, relatively small-scale executive actions to regulate the gun industry. In an opinion piece published in the New York Times late Thursday, Obama said he would not campaign for or support any politician in either party who does not support ­“common-sense gun reform.”

Meanwhile, the depth of antipathy to his message in some areas of the country has been clear.

While formally announcing his executive orders, President Obama said that "Second Amendment rights are important, but so are other rights" such as freedom of religion and freedom of assembly that have been cut short by gun violence. (Associated Press)

Gun sales soared again in the wake of Obama’s announcement. While polls show that expanding background checks to cover purchases at gun shows and online remains enormously popular, the American public is far more polarized on the broader question of restricting access to firearms.

Sen. Ted Cruz (R-Tex.), a presidential hopeful, sent a fundraising email to supporters that said “Obama wants your guns” and featured a doctored image of Obama in riot gear.

Cruz is “appealing to people’s anxieties and insecurities and outright fears in an attempt to win votes,” White House press secretary Josh Earnest said Thursday. “In some cases it veers into territory of being irresponsible, but that’s clearly what he’s up to. He’s not the only one.”

Last weekend, armed ranchers took control of a federal building in a wildlife refuge in eastern Oregon, arguing that they should have more freedom to operate on federal land and trying to wrest control from the U.S. government.

In a floor speech this week, Rep. Greg Walden (R-Ore.), who represents the area, joined other GOP lawmakers in expressing sympathy for the occupiers. Although Walden said the ranchers had “gone too far,” he added that he empathized with their anger.

That Obama’s forum was broadcast on cable news — which the president has said he almost never watches, because of the hyper-partisan discourse — shows how determined he is to break through the noise to reach the public.

The NRA called the show a “public relations spectacle orchestrated by the White House.” A CNN spokeswoman said the network approached the White House with the idea for the forum after the mass shootings in San Bernardino, Calif., last month and maintained complete editorial control.

The president fielded questions from a rape victim who opposes more gun restrictions, but also from gun-control advocate Mark Kelly, husband of former Arizona congresswoman Gabrielle Giffords, who survived a shooting in 2011. Giffords stood next to him.

“Part of the reason this ends up being a really difficult issue is that people occupy different realities,” Obama said.

Studies have shown that Americans living in a home with firearms are more likely to be injured by guns. But gun rights advocates have cited a half-dozen incidents in the past two years in which individuals have reportedly averted a mass shooting by opening fire on the potential perpetrator.

John R. Lott Jr., a conservative gun rights activist who heads the Crime Prevention Research Center who was not at the town hall, said in an interview that administration officials tend to gloss over the fact that people who have been victims of violent crime are more likely to own guns than those who have not.

Congress rejected a package of tighter gun laws in 2013 in the wake of the December 2012 elementary school shooting in Newtown, Conn. A frustrated Obama announced 23 small-scale executive actions later that year and two more in subsequent years. Aides said he was moved to act again in the wake of a shooting that killed nine people last fall at a community college in Roseburg, Ore.

The president visited that community in October to console family members. His motorcade drove past a crowd holding several dozen signs welcoming him — and an equal number protesting and making clear their opposition to any change to gun laws.

“Gun free zones are for sitting ducks,” one read.

On Thursday, Obama recalled visiting Newtown after the rampage there, which he has called the most difficult time of his presidency.

“It’s the first time I ever saw Secret Service cry,” he recalled. “It continues to haunt me.”

Scott Clement contributed to this report.