Lawmakers in New Hampshire are set to debate a measure Wednesday that would require any candidate who wants their name on the state's presidential primary ballot to provide a birth certificate.

But backers of the proposal say it isn't aimed at President Obama. 

Republican state Rep. David Bates told the New Hampshire Union Leader on Tuesday that supporters are amending the bill so that it wouldn't go into effect until 2013, having no impact on next year's presidential election. 

Bates told the paper that without that amendment, the proposal "created the appearance that it was all centered on putting barriers in the way of President Obama." 

Having it take effect in 2013, said Bates, would "diffuse any perception that this was directed at President Obama and is purely a policy decision designed to ensure that candidates for president are qualified according to the requirements if the Constitution." 

Despite the change, the bill is still generating opposition, and the Republican majority in New Hampshire's legislature is opposed to the plan. State House Majority Leader D.J. Bettencourt (R) said in a statement that the bill is "unnecessary and detracts from important business, namely our economy." 

Bettencourt also worried that, if passed, the measure could "represent a threat to our first in the nation primary as it gives other states reason and desire to try to jump us in line."

New Hampshire isn't the only state mulling such a bill. Lawmakers in close to a dozen other states across the country have introduced similar proposals that would force candidates to provide proof that they were born in the U.S. in order to qualify for the presidential ballot.  

Questions over whether Obama was born in the United States were first raised during the 2008 presidential campaign. Obama was born in Hawaii.