What does it take to create havoc in the capital of the most powerful country in the world? Anthrax? An orange terror alert? Massive anti-war protests? Another day like Sept. 11, 2001?

These days, it's a disgruntled farmer in a tractor.

"We live in a whole new era. You have to make a mental switch or you'll drive yourself insane," said Catherine Randazzo of North Potomac, Md., shaking her head in disbelief. "There's only so much you can do."

Dwight Watson, 50, of Whitakers, N.C., drove his tractor into a pond near Washington's monuments Monday. Since then he has kept law enforcement at bay. Streets remained closed for blocks, traffic was snarled for miles and several bus routes were altered.

People who live and work in Washington -- already jittery about the prospect of war, the possibility of retaliatory attacks and memories of jammed streets from the Sept. 11 attack on the Pentagon in Virginia -- are wondering how one farmer has created so much chaos for commuters.

Many asked how law enforcement could possibly stand up against a terrorist attempting a serious biological or chemical attack.

"It shows there's got to be a more defined way to get in and out of the city," said John Roellke, 43, of Arlington, Va., one of many whose daily commute turned into an excruciating journey. His usual 15-minute drive took an hour and 45 minutes.

"It's hard to figure out the best options in a situation like this," he said. "People are scared to take the Metro (Washington's subway). Driving will just put them at a standstill. The best thing must be staying at home and telecommuting."

Watson, a tobacco farmer, said government policies were forcing him out of business. Police, armed with automatic weapons, said he had claimed to have explosives, and they cordoned off an eight-block area around the large pond in Constitution Gardens, including the Washington Monument, the Vietnam Veterans Memorial and the Lincoln Memorial.

Phil Anderson, senior fellow for the International Security Program at Center for Strategic and International Studies, vouched for the way law enforcement was handling the standoff.

"It's disruptive and there is no easy solution, but there is no better way to protect the public than to establish a safe zone and to assume an explosive device is there," he said. "They want to resolve the issue peacefully, but the key question is how long do you let this go on?"

It's not the first incident of its kind in the capital.

In December 1982, Norman D. Mayer, a 66-year-old nuclear arms protester from Miami Beach, threatened to blow up the Washington Monument. Police evacuated nearby buildings and closed all streets in a several-block area around the National Mall during a 10-hour siege.

Mayer abruptly started driving away from the monument and threatened to become "a moving time bomb in downtown Washington." He was killed by a barrage of police gunfire. The truck was later determined not to contain explosives.

In the current standoff, police SWAT team members are positioned on an armored personnel carrier on Constitution Avenue, one of the main arteries through Washington. Several officers had rifles with sniper scopes aimed at Watson.

"It sounds like Washington police are following standard operating procedures," said Gerard Hoetmer, executive director of Public Entity Risk Institute, a Virginia-based organization.

"This is not unusual, it will happen again," Hoetmer said. "Washington is a place where people will make peaceful public demonstrations and sometimes go beyond the law."

Still, people are wondering how they'd evacuate in an emergency.

"We're definitely going to get stuck downtown and not get out fast enough," said DeAnn Kenney of Silver Spring, Md.