Sponsors of a new bill to fix the system for public financing of presidential campaigns are right that the present system has collapsed. Their plan for fixing it deserves careful consideration but has some problems.

The old system was created in 1974 to correct the fraud, bribery and exorbitant spending brought to light in the Watergate scandal. It worked reasonably well for nearly 30 years. Most Democratic and Republican candidates used the voluntary public financing system until 2000. But in the 2004 election, although both President Bush and his Democratic challenger, Sen. John Kerry of Massachusetts, accepted public financing for their general election campaigns, both opted out of the limits and matching funds for the primary election.

In the 2008 presidential primary campaign, most of the leading candidates have declined to accept matching funds and spending limits. And it looks as if one or both of the major party nominees will choose to spend unlimited amounts rather than using the public financing system.

So the old system has broken down, essentially because its spending limits and public subsidies fell short of the mounting costs of television time, high-priced consultants and all the other expenses of modern presidential campaigns. Sen. Susan Collins, a co-sponsor of the bill, notes that the front-loading of primary campaigns in decisive states requires more and earlier spending.

The solution in the proposed Presidential Funding Act of 2007 is mainly to raise the spending limits and raise the level of public matching money. Other provisions include requiring a candidate to qualify by raising $25,000 (instead of the present $5,000) in each of 20 states, with no more than $200 from any one contributor, and committing to accept public financing in both the primary and general elections. The voluntary income tax check-off would be raised and, like the spending limits, would rise with inflation.

Questions remain to be answered in hearings and debate on the bill. First of all, would the new limits and matching public subsidies be high enough to cover the surging costs of campaigns by the 2012 election when it would first apply? The two 2008 campaigns are expected to cost a combined total of $1 billion. If they were bound this time by the proposed limits, they could together spend no more than $500 million.

Second, can clever new schemes to get around the spending limits be anticipated and prohibited?

Third, why would higher figures on the income tax check-off hold greater appeal than the present figures?

Finally, don’t many Americans resent having their tax money spent on political campaigns?

After considering the pros and cons, Congress might do better by simply concentrating on making all campaign contributions transparent, so that the public would know who is trying to buy an election.