Barack Obama is rightfully being taken to task for going back on a pledge to rely on public financing if his opponent would do the same. John McCain is accepting the public financing, which comes with a restriction as to how much can be raised through private donations.
Obama is reportedly raising much more through private donations than he could through public financing, thus the decision to go back on his earlier pledge.
The idea of public financing is to reduce the influence of special interests on the election. This supposedly levels the playing field as far as campaign spending. Obama (or his advisors) claim that the argument of special interest influence is not valid in his case since his contribution base is very broad, with a rather modest average contribution.
Regardless of the degree of special interest influence, Obama should not go back on what he promised. Beyond that, the larger question remains of whether the government should finance political campaigns.
Among those who believe the playing field is not leveled as far as presidential elections are candidates of the Green, Libertarian, Natural Law and Socialist Workers parties. These and about a dozen other parties cannot reach the threshold needed to qualify for public financing, a threshold set at a level to exclude all but the two major parties.
A multi-party system at all levels of government is not necessarily desirable. Such a system operates with varying degrees of effectiveness in different nations of Europe.
However, the reality of the Republican and Democratic parties being tax supported entities is disturbing. That is a great deal better than a government sanctioned single party system but still shares the potential for excluding some ideas from public debate.
A better, but not perfect, approach would be to limit total spending by, or on behalf of, any one candidate.