A law to erect hundreds of miles of fence on the U.S.-Mexican border is on the books and money to start it has been okayed, but Republicans are nervous that now that they've lost control of Congress, they'll never see it built.

The law passed last year says Congress, now in control of Democrats who generally oppose the fence, don't have to release money to build it until they approve of how the fence will be built.

Based on the comments of some Democrats, there's no rush to make that happen.

Rep. Bennie Thompson, House Homeland Security Committee chairman, said he wants to see a plan for securing the northern and southern borders from Department of Homeland Security and hold a hearing on those plans instead of focusing only on fence construction and funding.

"My preference is to delay the construction of a fence until we have a plan," said Thompson, D-Ga.

House Majority Leader Steny Hoyer said this week Democrats still want to secure the border but want "the best possible way to do it."

Hoyer voted against the fence last year, along with House Speaker Nancy Pelosi, Thompson and 128 other Democrats in the House. In the Senate, 26 Democrats voted for the fence law, including Sen. Robert Byrd of West Virginia, who chairs the Appropriations Committee. Senate Majority Leader Harry Reid of Nevada voted against the fence.

The fence law dictates that in Texas a fence would stretch east out of El Paso; from Del Rio to Eagle Pass and Laredo to Brownsville, leaving a huge gap between Del Rio and Laredo. It also sets out locations in California and calls for fencing off the Arizona border from Mexico. Though the total fencing was believed to be about 700 miles, congressional researchers say it is closer to about 850 miles.

A separate law funding Homeland Security Department spending provided $1.2 billion for the fencing.

But that law also withholds $950 million of the sum until the House and Senate appropriations committees approve the department's plan for spending the money, giving those committees say over the design, location and length of the fence.

Attempts to get comment from the chairmen of the House and Senate appropriations committees were unsuccessful.

But Republicans have been pushing nonetheless, restating their arguments for a fence and dashing off letters to President Bush, asking him to request more money for the fence's construction in his 2008 budget.

In a recent news conference, fence backers Rep. Duncan Hunter, R-Calif. and Rep. Peter King, R-Iowa, ranking Republican on the House Homeland Security Committee, criticized recent estimates of the cost of erecting 854 miles of fencing as overblown.

"It's just a fence. It's the kind of fence we build in America every day," Hunter said., who sponsored legislation to build a fence in San Diego.

Hunter and King insist the fence would cost only $3 million a mile for a total cost of about $2.6 billion. That's the same estimate of the Congressional Budget Office.

But the Congressional Research Service report said in a Dec. 12 report, the budget office did not explain what costs it considered to reach that estimate.

The U.S. Army Corps of Engineers estimated a double-layer fence would cost a little over $1 million a mile, not including buying the land on which it would be built, according to the Congressional Research Service. In addition, maintenance could run from $16.4 million to $70 million a mile over 25 years, the Corps said.

The Department of Homeland Security has contracted with Boeing for the Secure Border Initiative, consisting of a "virtual fence" of cameras, surveillance technology and new procedures for border agents. The first phase is to be completed in Arizona in June.

A recent audit report said that project could cost between $8 billion and $30 billion, as much as 15 times the original $2 billion estimate.

Although she voted for the fence, Sen. Kay Bailey Hutchison, R-Texas, wants to adjust the law to respond to opposition raised by some local officials and business people. She arranged a closed door meeting scheduled for late Wednesday afternoon of Homeland Security Secretary Michael Chertoff and several of the border officials.

She said it's not the proper role of Congress to dictate specifics on where the fence should be built.

"It didn't seem like Congress was really in the real world" when it passed the law, Hutchison said.

The fence law is Public Law No: 109-367. The Homeland Security Appropriations bill with money for the fence is Public Law No. 109-295