MASSENA, N.Y. - Border Patrol agent Glenn Pickering slowed his rumbling snowmobile to a stop and eyed two trails of churned-up snow running down a riverbank.
They were snowmobile tracks leading out onto the ice of the frozen St. Lawrence River that runs between upstate New York and Canada. At night smugglers race across the ice with bags of marijuana. Pickering shielded his eyes with his hand as the wind covered the tracks; he couldn't see whether they went all the way across the border.
"There are all these islands out here, and the snowmobiles just come shooting across," Pickering said. "It's a constant battle."
This is the United States' forgotten border, where federal agents and police play cat-and-mouse with smugglers and illegal immigrants along 4,000 miles of a mostly unmarked and unfortified frontier with Canada. Unlike the southern border with Mexico, where drug-related violence has exploded in recent years, the northern border rarely makes headlines.
That changed this month after the U.S. Government Accountability Office released a report warning that the terrorist threat from Canada was higher than from Mexico because of the vast swaths of unprotected frontier. Just 32 miles of the 4,000-mile border have an acceptable level of Border Patrol security, with agents available to make on-site arrests, the report said.
Senators from northern border states urged the Obama administration to deploy military radar and more unmanned planes. The head of the Senate's Homeland Security committee, Conn. Sen. Joe Lieberman, suggested the government should examine whether to require visas of Canadian visitors.
"Our country is so focused on the southern border," said Rep. Candice Miller, R-Michigan, who will chair a hearing about the report on Tuesday. "At the same time the northern border is essentially wide open."
U.S. officials have said they are especially worried about extremists like Ahmed Ressam, the "millenium bomber" who was caught in 1999 trying to bring an explosives-filled car into the United States on a ferry from British Columbia. Ressam had planned to bomb the Los Angeles airport during the 2000 New Year celebration.
The GAO report also warned of "known terrorist organizations" in Canada. Since 2004 Canadian investigators have uncovered plots to bomb the country's main stock exchange, government buildings in Canada and targets in Britain.
Recent drug arrests have highlighted the border's porousness. In May, a Canadian kingpin confessed to running 2,000 pounds of marijuana a week through the forests of upstate New York. A gang arrested in November smuggled the narcotic painkiller OxyContin. And in December, Canadian officials arrested 29 smugglers on charges of using boats to run tons of marijuana, Ecstasy and methamphetamine across the Great Lakes to Michigan and New York.
President Barack Obama and Canadian Prime Minister Stephen Harper signed a Feb. 4 agreement to share more information on travelers and better coordinate cross-border investigations. The Department of Homeland Security has tripled the number of agents on the northern border in recent years and is building a $30 million intelligence-gathering center at a Michigan Air National Guard base.
Some critics say the Canadian threat is overblown, saying the volume of most drugs seized along its border is still a tiny fraction of 1 percent compared to seizures at U.S.-Mexico crossings. Residents complain that increased patrols are scaring away Canadian visitors.
"There are more drugs on Wall Street than here," said Jonathan Maracle, 35, who owns a gift shop on the 12,000-member Akwesasne Mohawk reservation, straddling New York and Canada on both sides of the St. Lawrence River. "All they're trying to do is make us look bad up here because they can't control up here. The United States government is nothing but bullies."
Few places show the challenges border agents face like the reservation, a frigid archipelago just downriver from where Pickering rode his snowmobile on a recent afternoon, offering The Associated Press a tour of his territory.
About 20 percent of all the high-potency marijuana produced in Canada - "multiple tons" each week - is smuggled through a patch of border less than 10 miles wide on the reservation, the U.S. Department of Justice reported in May. Since 2008, U.S. prosecutors say they have broken up four major smuggling rings operating on the Mohawk territory.
The river here is scattered with small islands that smugglers can use for cover as they hopscotch across the border in boats and snowmobiles. Thick forest on both sides provides cover from surveillance planes.
The political landscape is even more complicated than the geography. The Mohawk territory sprawls across both sides of the river and spills into both Quebec and Ontario.
Tribal leaders and police officials declined the AP's interview requests. But two huge signs at a main intersection spell out a common sentiment toward outside authorities threatening the tribe's autonomy.
"Yes, 'terrorists' come thru Akwesasne. They are N.Y.S.P. (state police), Border Patrol, ATF, FBI, etc., etc.!"
U.S. Border Patrol agents rarely go onto the territory without a tribal police escort, said Wade Laughman, agent in charge at the Massena Border Patrol.
"You get a lot of intimidation techniques: blocking in of your vehicles, people yelling at you, screaming at you, guys surrounding you," Laughman said. "It's not safe for one agent to go down there by himself."
Smugglers run contraband in both directions, Laughman said: marijuana, Ecstasy and methamphetamine come south while money, tax-free cigarettes, weapons and cocaine smuggled from Mexico goes north.
One admitted smuggler, Steven Sarti, described to a U.S. judge in May how he and an 18-man crew stuffed high-potency marijuana into black duffel bags used for hockey gear, then coded the bags with numbers representing different buyers. The gang smuggled 2,000 pounds of marijuana a week.
There have been no confirmed cases of terrorists coming through the reservation, but U.S. officials say they're worried it could happen.
"The folks we're dealing with, both in drug trafficking and terrorist activities, are not stupid," said James Burns, who directs Drug Enforcement Administration operations along the New York-Canada border. "We don't want to have anybody exploit a weak point."
Elsewhere on the border, tighter security around official border crossings is driving smugglers deeper into the wilderness.
In Sanilac County, Mich., Sheriff Garry Biniecki said his county's coastline on Lake Huron was a quiet place until 2008, when the government began installing sensors and cameras along the St. Clair River, to the south. The increased surveillance forced smugglers to cross Lake Huron instead of the river.
Soon residents in Biniecki's territory were reporting inflatable boats lurking offshore at night, strange goings-on at public boat ramps, and suspicious cars on deserted roads.
"Because so much pressure has been put down there, they're coming north," Biniecki said.
Still, many residents doubt whether the threat is real and chafe at border security measures.
In Waddington, N.Y., 20 miles west of Massena on the St. Lawrence River, visitors used to boat over from Canada to shop at the IGA or sip a beer at one of the four bars near the waterfront, said resident Herb Champion.
"Their Thanksgiving is Columbus Day, so they would come over here to buy their turkeys because it was cheaper," said Champion, 63.
The trips were technically illegal, but no one cared, he said. But in recent years federal agents have been stopping boats and even coming into bars to check IDs, he said. Three of the bars have closed for lack of customers.
"This used to be the greatest unsecured border in the world," Champion said. "Now everything's dried up."
Canadians, too, are worried about the "thickening" of the border, said Mark Salter, an expert on national security at the University of Ottawa.
Drug seizures and crime along the U.S.-Canadian border are nothing compared to what's smuggled across the southern border, he said. Canada's stronger economy and smaller population - about 33 million compared to 147 million in Mexico and Central America - also means there is less illegal immigration.
"There is simply not the scale of threat to the United States from Canada as there is from the southern border," Salter said.
About 7,500 pounds of marijuana coming from Canada were seized in 2009, compared with 3.2 million pounds seized on the southern border. However, agents seized six times as much Ecstasy on the northern border as on the southern border in 2009, the Justice Department said.
Marijuana seizures have doubled since 2007 in the Border Patrol's Swanton, Vt., sector, which covers northern New York, Border Patrol officials say. And the marijuana that Canada produces is much more potent than most Mexican varieties and sells for triple the price.
Opposition politicians in Canada have accused Harper, the prime minister, of buying into U.S. paranoia with the new border security agreement.
Fortunately for the United States, Canada has done a pretty good job of patrolling its own coastlines and identifying terrorist threats, said Michael O'Hanlon, a security expert at the Brookings Institution think-tank in Washington.
In the end, he said, the United States will probably have to live with much of its northern border unpatrolled.
"It's true, we're a little less rigorous" up north, O'Hanlon said. "But I'm not persuaded it's realistic to cover all of it."