In a development that flew largely under the radar on Thursday, the Senate beat back an attempt by David Vitter (R-LA) and Bob Bennett (R-UT) to add a citizenship question to the 2010 U.S. Census, with the goal of no longer counting non-citizens as part of states’ official populations.

Sen. David Vitter (R-LA) (Photo: Chattahbox)

The Vitter-Bennett proposal would have had a significant effect on the reapportionment of congressional seats that occurs after every decennial Census, with independent demographers predicting a loss of five seats for California and one each for New York and Illinois. 

On the whole, metropolitan areas where immigrants are strongly represented — think large, blue-state cities — would be disproportionately impacted. Leaving aside the troubling symbolism of no longer counting non-citizens,  Vitter-Bennett also would likely cause a major shift in the distribution of federal transportation funds, a sizable chunk of which are given out according to population-based formulas.

So urban residents can rest easy knowing that the Senate defeated the Vitter-Bennett plan, right?

Maybe not. The clash over how the Census should count immigrant residents is still raging, and Democratic strategist Simon Rosenberg said last month that he expects "the Republican assault on the Census and reapportionment" to continue apace.

And although Vitter-Bennett never came to an up-or-down vote last week, it’s worth looking at the vote to close off debate on the spending bill that served as a vehicle for the the Census issue. Every Republican voted to keep debating the bill, leaving the door open for Vitter-Bennett to be considered.