Barack Obama, the candidate for change, has changed his mind.

He won't take part in the public-financing system for the presidential election, despite saying last March that he would "aggressively pursue" an agreement with the Republican nominee to do just that.

For those who support public financing — as both Obama and his opponent, John McCain, profess to do — this development is a disappointing step in the wrong direction. The system was meant to level the playing field and remove the taint of special-interest influence by limiting each presidential candidate to $84.1 million in public money.

This will not happen. McCain has said he will take the public money, but Obama will use his powerful fundraising machine to collect far more in private donations. He is expected to outspend McCain by a 3-to-1 margin — at least.

Obama claims the system is broken. He rightly fears the unchecked torrent of money pouring into the Republican National Committee and the 527 groups, made famous for Swiftboating John Kerry in 2004. Obama contends that his brand of Internet fundraising — mostly small donations of $100 or less — is public financing of equal virtue. But it's unique to his campaign and not a proven solution.

Should Obama ride his superfueled campaign into the White House, he should live by his professed principles and work toward better ways to reform campaign financing.