Bush Signs Bill Authorizing 700-Mile Fence for Border

Without border agents to patrol the barrier, smugglers would blast holes in remote stretches, some critics have said. "The bill the president signed today represents the worst in election-year politics," said Rep. Silvestre Reyes (D-Tex.). "It is an empty gesture for the sole purpose of sending a false message about the security of our nation."

Though he signed the measure into law, Bush emphasized that other immigration changes are needed. "We have more to do," he said. ". . . We must reduce pressure on our border by creating a temporary-worker plan. Willing workers ought to be matched with willing employers."

Though the new law authorizes the construction of a 700-mile fence, it remains far from clear how much fencing will be built.

Department of Homeland Security spokesman Russ Knocke declined to say if the department is committed to building a 700-mile barrier. Instead, he cited the DHS commitment to test by next year a $67 million, 28-mile "virtual fence" that includes physical walls, vehicle barriers and remote monitoring south of Tucson.

Analysts, meanwhile, debate the effectiveness of a fence.

Since the United States began building a 66-mile barrier in San Diego in 1990, illegal immigration has been rerouted to more remote areas, with many migrants now being funneled through the treacherous desert south of Arizona.

Later in the day, Bush traveled to Iowa, where he campaigned for GOP congressional candidate Jeff Lamberti, a state senator who is trying to unseat Rep. Leonard L. Boswell (D). Campaign officials said the luncheon raised $400,000.

Bush then traveled to Michigan, where he headlined a fundraiser for GOP Senate candidate Mike Bouchard, who is trailing incumbent Debbie Stabenow (D). That event raised $700,000, officials said.

Weisman reported from Washington. Staff writer Spencer S. Hsu in Washington contributed to this report.