Sens. David Vitter, R-La., and Rand Paul, R-Ky., have introduced a bill to amend the Constitution "so that children born in the United States are only considered automatic citizens if one parent is a U.S. citizen, one parent is a legal immigrant, or one parent is an active member of the Armed Forces. They could also follow the traditional naturalization process to attain citizenship." Recall that Paul ran as a "constitutional conservative." There is nothing conservative about a radical constitutional revision, the need for which has yet to be established. Proponents of repealing birthright citizenship argue that scores of illegal immigrants come here to have "anchor babies," who can then help parents establish citizenship. This assertion is largely false. Studies by the Pew Hispanic Center and the Mexican Migration Project have demonstrated the drivers for immigration are jobs and family reunification. Roughly 80 percent of immigrant mothers in 2008-09 had been in this country since 2005, and 90 to 95 percent were here more than a year before having a child. Moreover, a child cannot, under federal law, help a parent attain citizenship until that child is 21. Dan Griswold of the Cato Institute doesn't think the Vitter-Paul proposal is going anywhere. As long as Americans understand "anchor baby" immigration is not a "widespread phenomenon," he contends, the idea won't get much traction.