WASHINGTON — Democratic presidential candidate Barack Obama says "mental distress" should not qualify as a justification for late-term abortions, a key distinction not embraced by many supporters of abortion rights.

In an interview this week with Relevant, a Christian magazine, Obama said prohibitions on late-term abortions must contain "a strict, well-defined exception for the health of the mother."

Obama then added: "Now, I don't think that 'mental distress' qualifies as the health of the mother. I think it has to be a serious physical issue that arises in pregnancy, where there are real, significant problems to the mother carrying that child to term."

Last year, after the Supreme Court upheld a federal ban on late-term abortions, Obama said he "strongly disagreed" with the ruling because it "dramatically departs form previous precedents safeguarding the health of pregnant women."

The health-care exception is crucial to abortion rights advocates and is considered a legal loophole by abortion opponents. By limiting the health exception to a "serious physical issue," Obama set himself apart from other abortion-rights proponents.

The official position of NARAL Pro-Choice America, the abortion-rights group that endorsed Obama in May, states: "A healthexception must also account for the mental health problems that may occur in pregnancy. Severe fetal anomalies, for example, can exact a tremendous emotional toll on a pregnant woman and her family."

The 1973 landmark abortion case, Roe v.Wade, established a right to an abortion, and a concurrent case, Doe v. Bolton, established that medical judgments about the need for an abortion could include physical, emotional and psychological health factors. "Senator Obama has consistently maintained that laws restricting abortions must contain exceptions for the health and life of the mother," Obama spokesman Tommy Vietor said Thursday. "Obviously, as he stated in the interview, he has consistently believed those exceptions should be clear and limited enough to ensure that they don't undermine the prohibition on late-term abortions."

Obama's position is similar to that taken by a bipartisan group of senators in 1998 who tried to counter efforts to ban certain late-term abortions with their own legislation. That proposal, which failed, would have banned all late-term abortions except for those that are necessary to protect the physical health of the mother.

In a statement, NARAL Pro-Choice said Obama's magazine interview is consistent with Roe v. Wade.

"Sen. Obama has consistently said he supports the tenets set forth by Roe, and has made strong statements against President Bush's Federal Abortion Ban, which does not have an exception to protect a woman's health," the organization's statement said.

A leading abortion opponent, however, said Obama's rhetoric does not match his voting record and his previously stated views on abortion rights.

David N. O'Steen, the executive director of National Right to Life, said Obama's remarks to the magazine "are either quite disingenuous or they reflect that Obama does not know what he is talking about."

"You cannot believe that abortion should not be allowed for mental health reasons and support Roe v Wade," O'Steen said.

In the interview with Relevant, conducted on Tuesday, Obama also defended his opposition to restrictions on induced abortions where the fetus sometimes survives for short periods. Obama voted against such a bill when he was in the Illinois Senate. He has said he supported a federal version of the law that contained more specific language because he feared the Illinois proposal would have applied to all abortions.

"There was a bill that came up in Illinois that was called the 'Born Alive' bill that purported to require life-saving treatment to such infants. And I did vote against that bill," Obama said Tuesday. "The reason was that there was already a law in place in Illinois that said that you always have to supply life-saving treatment to any infant under any circumstances, and this bill actually was designed to overturn Roe v. Wade, so I didn't think it was going to pass constitutional muster."

In other developments:

• Republican presidential candidate John McCain said Thursday in Mexico that a shake-up in the leadership of his campaign was part of a "natural evolution" as the organization becomes more national in scope.

McCain's campaign announced Wednesday that top adviser Steve Schmidt would assume a broad portfolio of duties, with nearly full control over message and strategy. Schmidt will report to Rick Davis, who will keep the title of campaign manager but focus on longer term matters like the Republican National Convention and McCain's choice of a running mate.

Addressing reporters at the conclusion of a three-day visit to Colombia and Mexico, the GOP nominee-in-waiting downplayed the personnel shift.

"Our campaign continues to grow, and the responsibilities are expanding and Mr. Schmidt is taking over some increased responsibilities," McCain said. "Rick Davis remains the campaign chairman, campaign manager. It's a natural evolution as we become more and more of a national campaign with increased staff and increased responsibilities."

• Obama struggled Thursday to explain how his upcoming trip to Iraq might refine, but not basically alter, his promise to quickly remove U.S. combat troops from the war.

A dustup over war policy — one of the main issues separating the Illinois senator from McCain — overshadowed Obama's town-hall meeting in Fargo, N.D., with veterans to talk about patriotism and his plans to care for them. Republicans pounced on the chance to characterize Obama as altering one of the core policies that drove his candidacy "for the sake of political expedience." He denied equally forcefully that he was shifting positions.

Arriving in Fargo, Obama hastily called a news conference to discuss news of a sixth straight month of nationwide job losses, but the questioning turned to Iraq policy and his impending trip there.

"I am going to do a thorough assessment when I'm there," he said. "I'm sure I'll have more information and continue to refine my policy."