WASHINGTON - President Bush wanted an exchange of workers with Mexico to bring order to the border, but wound up signing a law Thursday that approves partitioning 700 miles of the United States from its southern neighbor.

The administration once talked of "orderly migration" - workers entering the United States and returning to Mexico or other countries when their jobs were finished. But political realities have replaced phrases like that with "border security" and plans for fences, surveillance cameras, unmanned aerial vehicles and watch towers.

Bush still wants a guest-worker program. But the toughest resistance to that idea has come from his own Republican Party - and has intensified as the midterm elections have drawn near.

His White House signing ceremony for the new fence law - just 12 days before the November 7 elections - gave Republicans something to point to as they try to convince voters their party would do a better job of cracking down on illegal immigrants and keeping criminals and terrorists out.

"We're modernizing the southern border of the United States so we can assure the American people we're doing our job of securing the border," Bush said.

The new law also gives the Department of Homeland Security up to 18 months to achieve "operational control" of the border, defined as preventing all illegal entries into the US by land or water.

The bill didn't come with any new funding, and the US$1.2 billion that Congress previously approved is not enough to build the full 700 miles of proposed double-layer fence.

A 14-mile stretch under construction in the San Diego area is estimated to cost $126.5 million. Costs differ depending on terrain, environmental issues and whether private property is involved.

Sen. Jon Kyl R-Ariz., said Congress will add more money each year to erect the fence.

"Within about three years, we should have about 370 miles," said Kyl, whose state would be virtually sealed from Mexico through fencing and other barriers.

Customs and Border Protection Commissioner Ralph Basham said the fence could take many forms, from chain link to solid wall, depending on where it is placed. The shape will be determined with the help of Boeing Co., which was awarded a $67 million contract to install a high-tech "virtual fence" along 28 miles in Arizona.

"There is a will to get operational control of the borders and I believe they (lawmakers) are serious about this," Basham said. "It's going to mean Congress is going to have to stay serious about this and continue to fund it."

Skeptics say the money to build the full 700 miles will never materialize and the bill signing was merely a political gesture.

"The president and this Congress had a historic opportunity to pass a tough but fair immigration reform plan this year, but instead that chance was squandered by those Republicans who are more concerned about the ballot box than actually providing real solutions," said Sen. Edward M. Kennedy, D-Mass, a chief architect of the Senate legislation Bush had supported.

Bush continues to promote a temporary guest-worker plan. His administration had been negotiating the proposal with then-Mexican President Vicente Fox but shoved it into the background after the Sept. 11, 2001, terrorist attacks.

The public thinks Democrats can do a better job of handling immigration, by 44 percent to 37 percent, according to an AP-AOL News poll released Thursday.

But when people are asked specifically about putting a fence along the border with Mexico, a majority in another recent poll supported the fence. Polls over the past year show people have mixed feelings about immigration: They oppose providing illegal immigrants with easy access to the country but favor providing immigrants fair treatment once here.

A bill passed by the Senate would have allowed immigrants to remain and eventually become citizens after working, paying fines and back taxes and learning English. The House approved a separate bill that focused on enforcement measures such as subjecting those in the country illegally to felony prosecution. The two chambers failed to meet to negotiate a compromise before recessing for the elections.

The legislation Bush signed was a small portion salvaged from the House version.

Many Texas farmers and ranchers have land that touches the Rio Grande, the natural boundary, and fear a fence will cut through their properties and create an irrigation obstacle.

Bobby Sparks, who owns farm land that touches the river in the town of Progreso, said he's fed up with thieves coming across the river to steal batteries and other equipment.

"If they put it right on the bank of the river it would cut us off from our water, we don't want that. Other than that, if they gave me access to my water, I'm for a fence," Sparks said.

Rick Glancey, executive director of the Texas Border Sheriffs Coalition, said he hopes law enforcement officials and US Customs and Border Protection are in charge of determining where the fence goes.

"Many bureaucrats in Washington, D.C., have never seen the rural border and don't understand the unique problems we face," Glancey said. "Please don't let a policy wonk in D.C. decide."