"We see this legislation as a reach past that very foundation upon which this country was founded," Mr. Sanford told legislators in his veto. He called the bill a "further encroachment on our civil liberties and privacy rights."
The legislation required a DNA sample to be taken when people are arrested for felonies as well as for eavesdropping, peeping or stalking. Those samples could be destroyed if suspects are not convicted.
Mr. Sanford's action wasn't surprising given his veto of a similar bill last year. Mr. Sanford said Wednesday that government shouldn't have access to genetic information without a conviction, warrant or court order.
Extending that DNA collection to arrests breaches constitutional rights protecting people from illegal searches, Mr. Sanford said. He cited statistics showing only about 40 percent of the people arrested on felonies are convicted of those charges.
Meanwhile, Mr. Sanford said it was time to halt expansion of a state DNA database launched in 1994 for people convicted of sexual and other violent crimes. The database has been amended three times to cover all inmates serving time for felonies, misdemeanors with up to five years in prison and eavesdropping, peeping or stalking.
"Given the ever-expanding scope of the DNA database, we believe that it is finally time to draw a line in the sand and say that the DNA database will not be expanded to individuals who have not been convicted of a crime," Mr. Sanford wrote.
The veto was a blow to advocates hoping to allow inmates to use DNA testing to prove their innocence. Already, 43 states allow DNA tests to help free the wrongly convicted.
Mr. Sanford applauded that portion of the bill. "If this were the only provision of the law, we would have signed this legislation into law."
So far, DNA tests have exonerated 218 people nationwide. There's been one such case in South Carolina, in 1998, said Stephen Saloom, the policy director for The Innocence Project, a New York group advocating for use of DNA tests to free the wrongly convicted.
"It is a shame the Legislature had to attach the DNA database bill," Mr. Saloom said. "Freeing the wrongfully convicted and identifying the real perpetrator is too important to allow it to get caught up in political duels."
Legislators will decide whether to sustain or override the veto when they return in January. They fell well short of the two-thirds vote needed to do so last year, sustaining Mr. Sanford's veto with a 61-52 vote in the House.