WASHINGTON (AP) ­- Presidential candidate Howard Dean is surging in fund raising and winning over supporters, but leading centrist Democrats still have reservations about the viability of his candidacy.

“Dean has certainly created a lot of excitement and has hooked on to what is the hot button issue,” said Al From, founder and chief executive of the centrist Democratic Leadership Council. “His anti-war stance has helped him an awful lot. The enthusiasm is real. But in the long run, the Democratic Party will not elect a president who has not crossed a security threshold.”

Dean has vaulted to the top tier among the nine Democratic candidates, raising $7.5 million in the second quarter of fund raising and gaining thousands of followers through the Internet. His staunch opposition to the U.S.-led war against Iraq does not go over well with centrist Democrats, however, whose leaders circulated a memo in May that suggested Democrats could lose badly in 2004 if the former Vermont governor were their candidate.

On the eve of a Democratic Leadership Council summer meeting in Philadelphia, From said it was essential that the Democrats have a nominee strong on national security to compete with President Bush.

Bruce Reed, the council’s president, said, “If Dean were campaigning more like the way he governed, he would be in much stronger shape for the long haul.” Dean, a medical doctor, was known as a fiscal conservative during his tenure in Vermont.

The Democratic Leadership Council decided against inviting the nine candidates to its meeting Sunday and Monday.

“What happens is when you have the candidates, they are all trying to get advantage, and the focus is on how they’re trying to do that,” From said.

“You don’t have a chance to focus on message, ideas and the strategy.”

The DLC will feature instead governors who won in conservative or swing states, including New Mexico’s Bill Richardson, Janet Napolitano of Arizona, Kathleen Sebelius of Kansas, Jim McGreevey of New Jersey, Ed Rendell of Pennsylvania and Mark Warner of Virginia.