Homeland Security officials counter that modernizing border facilities should be a national priority. US Customs and Border Protection received $420 million in federal stimulus funds to renovate ports of entry along the Canadian and Mexican borders.

“The whole thing is a perfect example of waste,’’ said Glen Gurwit of Swanton, a customs inspector for 31 years who frequently worked at Morses Line before retiring in 2004. He said the port is used mostly by locals crossing to visit relatives, play hockey, or shop, and is notable for its “peace, quiet, and isolation.’’

The family’s many supporters in the area do not dispute that the Morses Line facility, some 50 miles southeast of Montreal, is outdated. But they do not understand why the government needs to spend millions on it.

“It’s like taking a leg off a stool. If you reduce the hay, you reduce the herd; if you reduce the herd, you immediately affect the viability of the farm,’’ Brian Rainville said. “Last year, the farm lost money. Right now, we are hanging on by our fingernails.’’

The Rainvilles say the land, where they grow a portion of the feed for 150 head of cattle, is worth far more than the offer, and is critical at a time when the low price of milk has dairy farmers struggling to cover the cost of production.

“They are trying to steamroll us,’’ said Brian Rainville, 36, a high school government and civics teacher whose grandfather bought the farm in 1946 and whose parents and two brothers run it now. “We have a buyer holding a gun to our head saying you have to sell or else.’’

It intends to acquire 4.9 acres of border land on a dairy farm owned for three generations by the Rainville family. Last month, the Rainvilles learned that if they refuse to sell the land for $39,500, the government intends to seize it by eminent domain.

The Department of Homeland Security sees Morses Line as a weak link in the nation’s borders, attractive to terrorists trying to smuggle in lethal materials. The government is planning an estimated $8 million renovation here as part of a nationwide effort to secure border crossings.

The bucolic setting of silos and sugar maples has become the focus of a bitter dispute that pits one of America’s most revered traditions — the family-owned farm — against the post-9/11 reality of terror attacks on US soil.

FRANKLIN, Vt. — The red brick house sits unassumingly on a sleepy back road where the lush farmlands of northern Vermont roll quietly into Canada. This is the Morses Line border crossing, a point of entry into the United States where more than three cars an hour constitute heavy traffic.

Morses Line, one of 15 ports between Vermont and Quebec, was among the first in the country slated for repair. It was built in 1934. Its only detention facility is a set of handcuffs attached to a wooden bench. It has no place to inspect vehicles, so customs officers have to do it in the middle of the road. It has a road gate that they have to open and close manually. Its roof leaks.

“It is unsafe,’’ said Marco A. Lopez, spokesman for US Customs and Border Protection.

Lopez said the government has been cooperating with the Rainvilles, and responded to their concerns by scaling back an earlier plan to use 10 acres of the farm.

Allison Stanger, director of the Rohatyn Center for International Affairs at Middlebury College, said the government is right to shore up aging, little-used border crossings.

“If there’s a weak link in the chain, that’s precisely what our enemies would target for getting things into the country,’’ she said. “It seems far-fetched to think that something like this could happen in beautiful Vermont. But before it happened, what American would have thought that someone would fly a plane into a building?’’

The Rainvilles suggest that the Morses Line port, where only 14,811 vehicles crossed in 2009, could be shut down altogether. They say the stimulus money would be better spent upgrading the busy Highgate Springs port 11 miles to the west, where Interstate 89 connects with a Canadian route to Montreal. Hundreds of thousands of vehicles cross there each year.

US Senator Patrick Leahy, a Vermont Democrat who supports the family, raised the idea of closing the Morses Line port with Department of Homeland Security Secretary Janet Napolitano last month. Napolitano promised to hold a public hearing Saturday in Franklin, Vt., the town that includes Morses Line.

Lopez said the government has already hired a contractor, but he added that officials will hear out opinions voiced at the meeting.

“All options are on the table,’’ he said. “If the community and the state and whatever disagree with us, we will talk to Canada about closing the border.’’

The Rainvilles say they have nothing against border officials. Two years ago, they closed the farm so that law enforcement agencies could use it to conduct a drill on the response to a nuclear, biological, or chemical attack. But they were rankled by a recent government assessment that described the 4.9 acres as undeveloped and insignificant to their operation.

The plot is a fraction of their 220-acre property, but it constitutes about one-twelfth of their available hay land. It yields 1,000 bales of hay a year; without it, the family would need to buy the hay at $3.25 a bale, and possibly reduce the number of cows, said Craig Rainville, 32.

He calculates that the cost would soon exceed the sum the government is offering, and cripple a farm that has been named to the National Register of Historic Places for its intact 19th-century buildings and pristine landscape and designated a Dairy of Distinction by the Vermont Department of Agriculture.

The family recently put up a “Save This Farm’’ sign at the entrance to the property.

Last week Brian Rainville stood on a field of alfalfa and indicated orange posts erected by government surveyors to delineate the boundaries of the disputed plot.

“They look at it like a vacant lot,’’ he said. “They do not understand how vital that land is to who we are and what we do.’’

© Copyright 2010 Globe Newspaper Company.