Barack Obama's campaign website is recommending that voters remain registered in battleground states even though they may not be living there on Nov. 4.

The Republican National Committee (RNC) is raising questions about how Sen. Obama’s (Ill.) campaign is urging its supporters to vote in purple states despite living in red or blue states this fall.

However, Columbia University law professor and election law expert Nathaniel Persily stated that “there is no problem” with what Obama is doing. He noted that thousands of voters will be eligible this year to vote in one of two constituencies.

The Obama voter registration website asks people where they will be living on Election Day and makes a recommendation of whether they should switch their registration upon moving or whether they should remain registered at their old address and vote via absentee ballot.

For example, a prospective Obama voter who indicates that he will live in conservative-leaning Alabama on Election Day but is currently registered in the battleground state of Pennsylvania is informed that he has a choice where to vote but that it is “recommended” that he vote in Pennsylvania by absentee ballot. [A screengrab illustrating this scenario can be viewed here .] Meanwhile, voters moving from Alabama to Pennsylvania are informed that it is recommended that they vote in their new home state.

The website of Republican presidential nominee Sen. John McCain (Ariz.) does not encourage Americans to vote in one state over another if they are eligible to vote in both.

“This isn’t done for any good government reason,” the RNC official said. “It is done for one reason only. They deem it as politically expedient to do this.

“They are encouraging voters who are taking up residence somewhere else to not vote there,” the RNC official argued, adding that the Obama campaign is “giving what amounts to legal guidance to voters and tell[ing] them this is OK.”

The Obama campaign responded that there is nothing improper about the website.

“Voters may still vote by absentee ballot if they meet the residency requirements of a state that they will not be present in on Nov. 4 — such as students,” said Obama spokesman Nick Shapiro. “The purpose of the website is to provide voters the necessary information about where and how to register, where to apply for an absentee ballot, or to check their polling location, with ease.”

The RNC is “taking a look at [its] options,” the GOP official told The Hill, arguing that the registration effort does not “square with their rhetoric” on the electoral process and “sheds light on how they view the voter.”

But Shapiro retorted that “repeated efforts have been made by partisan players to confuse students about the rules of eligibility for registering, and the campaign is determined to give students the correct information so that they have all the tools necessary to register and vote wherever they are eligible.”