"I am not a birther, I am an enemy of the birthers," Matthews said on his show "Hardball." But "why has the president himself not demanded that they put out the initial documents?"
The administration has been reluctant to be seen as bowing to politically motivated extremists whose views are not substantiated. As a citizen, Obama is also entitled to privacy rights under the law.
"A year and a half ago, I asked that the birth certificate be put on the Internet because, Lord knows, if you have a birth certificate and put it on the Internet, what else could be the story?" White House press secretary Robert Gibbs told reporters in July 2009. "Nothing will assuage them. ... But there are 10,000 more important issues for people in this country to discuss."
The nonpartisan group FactCheck.org determined the document was authentic, writing on its blog, "Obama was born in the U.S.A. just as he has always said."
Archives of two local papers -- the Honolulu Star Bulletin and Honolulu Advertiser -- also contain birth announcements for a young Obama son in early August 1961.
Still, 14 percent of Americans say, without prompting, that they think Obama was born in another country, according to the most recent ABC News-Washington Post poll.