"I made the commitment to the American people that if I were the nominee of my party, I would accept public financing," McCain said Friday in Oshkosh, Wis. "I expect Senator Obama to keep his word to the American people as well. This is all about a commitment that we made to the American people.
"I am going to keep my commitment," he said. "The American people have every reason to expect him to keep his commitment."
Obama spokesman Bill Burton on Thursday called public financing "an option that we wanted on the table," but said "there is no pledge" to take the money and the spending limitations that come with it.
McCain said that if Obama becomes the nominee and decides against taking public money, he might do the same.
"If Senator Obama goes back on his commitment to the American people, then obviously we'd have to rethink our position," McCain said. "Our whole agreement was that we would take public financing if he made that commitment as well. And he signed a piece of paper, I'm told, that made that commitment."
Early in the race, Obama asked the Federal Election Commission whether he could raise general election money during 2007 but return it if he chose to accept the public funds.
Also, in response to a questionnaire in November from the Midwest Democracy Network, a group of nonpartisan government oversight groups, Obama said: "Senator John McCain has already pledged to accept this fundraising pledge. If I am the Democratic nominee, I will aggressively pursue an agreement with the Republican nominee to preserve a publicly financed general election."
McCain would be the obvious beneficiary if they both take the federal money because they would have to return money already raised toward the general election. Obama has raised $6.1 million for the general, nearly three times as much as McCain's $2.2 million.
If the candidates reject public funds it would be historic rejection of the public financing system. No major party candidate rejected public funds for the general election since the system was put in place in the 1970s after the Watergate scandal.
Candidates who accept public funding are eligible for about $85 million, which is paid for by a $3 checkoff on IRS tax return forms.