LAS VEGAS — The ability of the federal government to enforce its own land policies in the West will be tested as a trial begins this week of a Nevada rancher accused of leading a 2014 armed standoff with federal agents in a dispute over cattle grazing.

Federal prosecutors in Nevada have twice before failed to win full convictions at trial of men who had guns during the tense confrontation involving hundreds of protesters who stopped government agents from rounding up cattle belonging to Cliven Bundy.

In opening statements Tuesday prosecutors will accuse the 71-year-old Bundy, sons Ryan and Ammon Bundy, and co-defendant Ryan Payne of enlisting a self-styled militia to defy government authority.

"If they don't convict the Bundys, it will look like the federal government can't enforce its own land policy," said Ian Bartrum, a University of Nevada, Las Vegas, law professor following the case closely. "The Bundys and people like the Bundys have been fighting this battle for decades, and always lost."

The standoff near Bunkerville, Nevada, about 80 miles northeast of Las Vegas, became an iconic moment in a decades-long turf battle between the government agency assigned to manage vast tracts in the Western U.S. and ranchers whose cows graze the land.

Bundy argues that his family has used the same public range for more than a century — even before the 1934 Taylor Grazing Act set federal land policy. He maintains the land belongs to the state, not the U.S. Bureau of Land Management.

Defense attorneys say the four men didn't conspire with anyone, didn't wield weapons and didn't threaten anybody. They cast the standoff as a peaceful protest, with no shots fired and no one injured before overreaching government officials abandoned the cattle round-up and went home.

"I think they'll lose again," Bundy attorney Bret Whipple said, pointing to the prosecutorial scorecard after trials that ended in April and August: Two defendants acquitted; two defendants convicted of some charges; two defendants now free after pleading guilty to misdemeanors to avoid standing a third trial. No one was found guilty of conspiracy.

Acting U.S. Attorney Steven Myhre, the lead prosecutor, declined to comment outside court last week.

During previous trials, he has accused the Bundys of trying to instigate a "range war" against the government. He said federal agents were enforcing federal court orders after Bundy racked up more than $1.1 million in unpaid fees and penalties letting his cattle graze for decades in what is now Gold Butte National Monument.

The Bundys and Payne have been jailed since early 2016. They remain shackled at the ankles in court, but blow kisses to family members in the audience.

Each man refused to enter a plea, saying he didn't recognize the authority of the government. A magistrate judge entered not-guilty pleas for each.

The men faces 15 felony charges that include assault and threats against federal officers, firearms counts, obstruction and extortion. Stacked together, convictions on all charges carry the possibility of more than 170 years in prison.

The April 2014 standoff was a precursor to an early 2016 protest in rural eastern Oregon, where Ryan and Ammon Bundy and Payne led a 41-day takeover of a federal facility and called for the U.S. government to turn over public land to local control.

No one disputed the men occupied the Malheur Wildlife Refuge. But a federal jury in Portland refused to convict Ryan and Ammon Bundy of any crime. Payne pleaded guilty before trial to felony conspiracy to prevent Interior Department employees from doing their jobs, but is fighting to withdraw his plea and his expected sentence of more than three years in prison.