Fears of a superhighway from Mexico to Canada

Telegraph: Texans fear US sovereignty will disappear down superhighway

If it were built, the road would be one of the engineering wonders of the 21st century -a trade route a quarter of a mile wide, carving a path from Mexico through the heart of America to Canada.

In its most radical form, it would allow lorry drivers to travel hundreds of miles from the Mexican border deep into the US before reaching customs and immigration controls in Kansas.

Backers of the idea, labelled the "Nafta Superhighway", after the North American trade pact, say it would revolutionise patterns of commerce across the continent and enhance the economic prospects of millions. But its critics say it could spell the end of US sovereignty.

With costs estimated at $183 billion (£94 billion), the 1,200 ft wide road would consume one million acres in Texas alone. Construction could take up to 50 years.

However, officials of the federal government in Washington deny that there is any transnational plan. A member of the Department of Transport told a congressional committee this month that all the government wanted to was improve existing roads.

Many conservatives disagree. They link the highway to agreements being negotiated behind closed doors between the Mexican, American and Canadian governments that they believe will transform the North American Free Trade Association into an EU-style superstate. They point to an agreement signed by Mr Bush, Vicente Fox, then president of Mexico, and Paul Martin, then Canada's prime minister, in Waco, Texas, in March 2005.

Republican Ron Paul, a Texas congressman, says it is part of a drive for "an integrated North American Union" - complete with a currency, a cross-national bureaucracy and borderless travel. "It would represent another step toward the abolition of national sovereignty," he said.