On Thursday, the Republican architects of the Senate bill — including Senators John McCain of Arizona, Lindsey Graham of South Carolina, Mel Martinez of Florida and Chuck Hagel of Nebraska — supported the decision to bring the fencing measure to a final vote. The lawmakers, who still favor the legalization of illegal immigrants, have said they view the fence as one step toward achieving their broader legislative goals.  One Republican, Senator Lincoln Chafee of Rhode Island, voted against shutting off debate on the fence. Eighteen Democrats voted in favor of it.  Senator Jeff Sessions, Republican of Alabama, described the vote as a crucial effort toward stopping the flood of illegal immigrants pouring into the United States.  “We know that fencing works,” Mr. Sessions said. “It’s time to make it a reality. Then we’ll have some credibility with the American people. Then we can talk comprehensively about how to fix an absolutely broken immigration system.”  Senator Edward M. Kennedy, Democrat of Massachusetts, derided the bill as “a good-feel, bumper-sticker vote” intended to energize conservative voters before the midterm elections. He noted that nearly half of the illegal immigrants in the country entered the country legally, without sneaking across the Mexican border, and overstayed their visas.  “This is a waste of money,” Mr. Kennedy said. “It isn’t going to work, and it’s going to be enormously costly.”  The fence is one of several border security measures the Senate hopes to pass this week before Congress recesses to campaign for the Nov. 7 elections. On Monday, House and Senate negotiators agreed to provide $1.2 billion for several hundred miles of fencing as part of a $34.8 billion spending plan for the Department of Homeland Security for the coming year.  The border security spending is one of several major policy initiatives that Congressional leaders decided to insert into the annual appropriations bill. It includes money to hire 1,500 new Border Patrol agents, increasing the force to 14,800, and to add 6,700 detention beds. The $1.2 billion for border security is designated for a traditional fence, vehicle barriers and a so-called virtual fence, which includes lighting, cameras and ground sensors.  The fence would be built near Tecate, Mexico, and Calexico, Calif.; Columbus, N.M.; and El Paso, Del Rio, Eagle Pass, Laredo and Brownsville in Texas.  Senators still sparred late into the night on Thursday, however, over two amendments to the fencing measure.  One amendment, proposed by Senator Kay Bailey Hutchison, Republican of Texas, would require the Department of Homeland Security to work with state and local officials in border states to determine where the fencing should be.  The second amendment, proposed by Mr. Martinez, would give the secretary of homeland security greater flexibility in determining when operational control of the borders is achieved.  A version of this article appears in print on , on Page A18 of the New York edition with the headline: Senate Moves Toward Action On Fence on Mexican Border. Order Reprints| Today's Paper|Subscribe
The bill would require construction of two layers of reinforced fencing in stretches of California, Arizona, New Mexico and Texas.