April 1 (Bloomberg) -- Democratic presidential candidate Hillary Clinton, campaigning in Pennsylvania, defended herself against claims she has wavered on the North American Free Trade Agreement, a deal that's unpopular in much of the state.

Clinton, a New York senator, told reporters in Philadelphia that she fought against Nafta during the 1992 presidential campaign of her husband Bill and again in White House meetings as first lady. She said she refrained from public criticism after Bill Clinton opted to support the 1993 trade agreement.

``The president made a decision,'' she said today. ``You're part of an administration. I believe you support the president, and I did.''

Clinton's position on Nafta is critical in Pennsylvania, a state that's lost more than 200,000 manufacturing jobs since her husband left office in 2001. Clinton's rival for the Democratic nomination, Illinois Senator Barack Obama, has accused her of changing her stance when she started running for president.

``It's undeniable that the Clintons pushed Nafta, and then during our debate she said she wasn't in favor of Nafta,'' Obama said on March 29 in Johnstown, Pennsylvania.

Earlier today, labor leader Gerald McEntee introduced Clinton, 60, at an event in Philadelphia and backed up her account of the White House years, saying that she called him the day Nafta passed and said, ``We lost.''

Concerns About Timing

Others involved in the effort, including former Labor Secretary Robert Reich, have said Clinton's concerns were mostly about timing; she favored pushing for passage of her universal health-care plan first.

``I thought health care should be the priority more than Nafta, which had been inherited from the Bush administration,'' Clinton said today, referring to former President George H.W. Bush. ``I thought the side agreements, which included labor, environmental standards, were not strong enough.''

Obama, 46, is also focusing on trade issues as he campaigns across Pennsylvania. Today, he spoke in the northeastern town of Wilkes-Barre just before Clinton visited, saying the U.S. should drive a harder bargain with trading partners such as China.

``We should be tough negotiators with other countries,'' Obama said. ``It's one thing when China was shipping goods in back in the '60s and '70s, when we were the dominant economy. It's another thing when they are growing much faster than us and are a major competitor.''

Pennsylvania holds the next contest in the race for the presidential nomination, an April 22 primary with 158 pledged delegates at stake. Clinton is vowing to stay in the race even if the fight carries into the convention. While she's favored in Pennsylvania, she lags behind Obama in the overall number of delegates awarded by elections and caucuses.

Obama has 1,414 pledged delegates to Clinton's 1,250, according to an unofficial tally by the Associated Press. She leads in the number of endorsements from the 794 so-called superdelegates, 256 to 218, according to lists supplied by the campaigns and interviews.

To contact the reporter on this story: Kristin Jensen traveling with the Clinton campaign at kjensen@bloomberg.net

Last Updated: April 1, 2008 16:18 EDT