This vote occurred on an amendment by Jim DeMint, R-S.C., that would require immigrants obtaining a new "Z visa" to obtain health insurance coverage.

The "Z visa" would be established by the underlying bill, which would overhaul America's immigration policies. This new visa would allow qualifying immigrants, including those currently in the country illegally, to work legally in the United States while they are set on a path to citizenship. They could become citizens in 13 years under this program.

DeMint said that the underlying bill contains no provisions to ensure that illegal immigrants applying for the new visa would have health care coverage. "That means they will continue to be a heavy burden on the American health care system," DeMint said. "The least we can ask of these immigrants we are granting permanent legal status in this country is not to be a burden on Americans for their health care. To have a minimum level of health insurance is the least we can ask."

Ted Kennedy, D-Mass., who cosponsored the underlying bill, said that the bill already anticipates this situation, and requires that Z visa applicants pay a $500 fee that will be redirected to local communities to help defray health care costs. Kennedy said the real effect of DeMint's amendment would be to discourage otherwise deserving people from applying for the visas.

"The idea that we are going to put this in as a requirement is another way of saying to those individuals, look, we might like other provisions of the legislation, but this is a way of effectively barring you from being able to participate in this program. That undermines the object of a very important aspect of this whole endeavor. Therefore, I hope the amendment will be defeated," Kennedy said.

This goes to the heart of the debate over whether or not the estimated 12 million illegal immigrants currently living in America should be given a chance at citizenship (often called "amnesty") even though they have violated the law by being here illegally, or be deported. Though these questions sometimes split down regional rather than partisan lines, Democrats generally favor some sort of partial amnesty, such as what is achieved with the Z visa.. Republicans generally oppose any such attempts, believing that amnesty essentially rewards immigrants that have flouted U.S. immigration laws, even as others have patiently waited their turn at legal citizenship.

By a vote of 43-55, the Senate rejected DeMint's amendment. All but three Democrats voted against the amendment; the three voting yes were Robert Byrd of West Virginia, Claire McCaskill of Missouri and Ben Nelson of Nebraska. Most Republicans voted for the amendment, with the exception of eight who voted no. Thus, the bill went forward without language that would have required people obtaining a new "Z visa" to secure health care coverage.