Meeting in the small town of Claremont in New Hampshire, the former Democratic senator Bill Bradley and Senator John McCain shook hands and signed a pledge to limit the amount and nature of financial contributions, should either become President.
"Although we disagree about many things," Mr Bradley said, "we join together for a higher purpose: to bring an end to the plague of money in our politics."
Mr McCain added: "We should be fighting the battle of ideas, not the battle of bucks."
While the event was dubbed by reporters, "the summit of the underdogs", both Mr Bradley, who is challenging Vice-President Al Gore for the Democratic nomination, and Mr McCain, who is emerging as the chief rival to George W Bush for the Republican nomination, have attracted unexpectedly strong support to the point where they have a chance of winning their respective primary elections in New Hampshire.
Polls show that disgust with the role of big money in politics is a major reason for the steady decline in turnout even in national elections and the widespread contempt felt towards politicians. Many supporters of Mr Bradley and Mr McCain are political neophytes who aredrawn to these campaigns by the donations issue alone.
Both Mr Bradley and Mr McCain want an end to so-called "soft money" contributions, the huge donations made mostly by big business to campaign coffers, which are made - many suspect - in the expectation of favourable treatment by legislators. Whether impropriety exists is disputed, but the practice - both Mr McCain and Mr Bradley believe - gives the "impression" of impropriety.
While agreeing wholeheartedly that reform is needed, the two disagree about exactly what form it should take. Mr Bradley favours the use of public money to fund campaigns; Mr McCain would require all contributions to be made by individuals and not by organisations or companies. They voiced their differences clearly yesterday, plainly aware they are also competing for votes.
Long-time proponents of campaign finance reform, neither can be accused of "sour grapes". Mr Bradley in particular is an expert fundraiser in the current system, and Mr McCain's contributions are gathering pace, although they both lag behind Mr Bush's spectacular fundraising run. Their acceptance of donations from big business has led to accusations of hypocrisy, but they contend that until the system is changed they have no choice.
There is fierce resistance to change from those who benefit most by the current arrangements. The most recent attempt at reform was rejected by Congress earlier in the year.