Barack Obama's decision to opt out of the public financing system will pay dividends for him down the road -- so many dividends, in fact, that it would have been positively silly for him not to opt out. But in the meantime, John McCain's campaign isn't going to let him get away without paying at least some political price for breaking earlier promises.

In a statement she released after Obama's decision was made public, McCain communications director Jill Hazelbaker said:

Today, Barack Obama has revealed himself to be just another typical politician who will do and say whatever is most expedient for Barack Obama.

The true test of a candidate for President is whether he will stand on principle and keep his word to the American people. Barack Obama has failed that test today, and his reversal of his promise to participate in the public finance system undermines his call for a new type of politics.

Barack Obama is now the first presidential candidate since Watergate to run a campaign entirely on private funds. This decision will have far-reaching and extraordinary consequences that will weaken and undermine the public financing system.

But Obama spokesman Bill Burton blames the McCain camp for forcing Obama's hand on this. "In the past couple of weeks, our campaign counsels met and it was immediately clear that McCain's campaign had no interest in the possibility of an agreement," Burton said. "When asked about the RNC's months of raising and spending for the general election, McCain's campaign could only offer its expectation that the Obama campaign would probably, sooner or later, catch up. And shortly thereafter, Senator McCain signaled to the 527s that they were free to run wild, without objection."

Of course, by every indication, the Obama campaign will catch up to -- and then overtake -- the combined spending of both McCain's campaign and the Republican National Committee.

Additionally, the Chicago Sun-Times' Lynn Sweet points out that during a February debate, Obama told the late Tim Russert, "At the point where I'm the nominee, at the point where it's appropriate, I will sit down with John McCain and make sure that we have a system that works for everybody." There was no such sit-down.