This vote was on an amendment by Tom Coburn, R-Okla., that would require completion of several border initiatives as part of the bill's "enforcement triggers." The initiatives in Coburn's amendment include building a 700-mile fence across the U.S.-Mexico border; integrating all federal databases with information about immigrants; fully implementing US-VISIT, the system that uses biometrics to keep known terrorists and criminals from entering the U.S.; prohibiting states and local governments from adopting policies that prevent law enforcement from asking about someone's immigration status; and several other items. In essence, the amendment would require that these immigration and security initiatives be fully implemented before certain other provisions in the underlying bill could be put into effect.

The amendment was offered to a measure that is intended to overhaul the nation's immigration system. The bill represents a hard-won compromise between competing sides of the immigration debate: those who want to give the nearly 12 million illegal immigrants a chance to legitimize their residency either temporarily or permanently, and those who want to tighten security along America's border with Mexico. To that end, the bill would establish several new visas that allow immigrants to work temporarily or put them onto a path to citizenship. But for these visas to be activated, the government must first certify that several other initiatives intended to strengthen America's border included in the underlying bill have been implemented – the bill's so-called "enforcement triggers." Coburn's amendment would add the border security initiatives in his amendment to the bill's list of enforcement triggers.

‘This amendment is the first step to help restore some of the trust Congress has lost. It says that before this bill can go forward, the President must demonstrate to Congress, and Congress must agree, that current laws are being enforced—laws that are on the books," Coburn said. "This amendment is common sense. If the agencies can demonstrate that U.S. borders are secure and immigration laws are enforced, then the American people have reason to believe that this time things will be different. They will demonstrate that compassion, once again, so often seen in the past."

Ted Kennedy, D-Mass. and one of the authors of the underlying bill, agreed that his bill's security measures "may not be perfect," but that it does go a long way to improving security in a comprehensive way.

"We have followed what has been recommended by the Department of Homeland Security to get the best security we could. But the idea that we are going to suspend some of those elements which have been intertwined—and as Secretary Chertoff said very eloquently: ‘You need them all.' I appreciate the fact that the good Senator from Oklahoma says: ‘Well, let's hold certain parts back until we get everything in place.' Our answer is: ‘You better start getting everything in place if you really want to have a secure border.'"

The Senate defeated Coburn's amendment on a vote of 42-54. Republicans were largely in favor of the amendment, though 16 voted no. Democrats were largely against the amendment, though 11 voted yes. Thus, the bill went forward without language that would have required the implementation of several border security initiatives, including a 700-mile border fence, in order to issue new visas the bill would create.