John McCain's June 3 speech in New Orleans was widely panned by his fellow Republicans, who criticized both his delivery and his timing, as it was a day dominated by Barack Obama's finally clinching the Democratic nomination. But some Republicans were heartened by the content of the speech, because McCain embraced the theme of reform that they believe is his only path to victory in November.

Yuval Levin made the argument well in an essay in these pages ("A Theme for McCain's Pudding," May 26). The "change" the public wants in politics, he observed, is for the government to respond to the swift and sometimes disconcerting alterations in American life. So, for example, we have a health care system shaped by rules enacted decades ago, when health care was cheaper (since it couldn't do much) and labor was less mobile than it is today. Levin's prescription is a set of conservative reforms to modernize the system to meet today's needs. McCain is temperamentally suited, as Levin also notes, to the role of the restless reformer.

Levin is, perhaps, too diplomatic to note two political advantages to the reform theme. The first is that a credible conservative reformism would distance McCain from Bush without alienating the president's remaining supporters. Instead of carefully picking areas of agreement and disagreement with the last seven years, McCain would be able to change the subject to tomorrow. The second is that an emphasis on modernization would undercut the ongoing Democratic campaign to depict McCain as old and out of touch. His proposed reforms would be the programmatic equivalent of the vigor he needs to project.

There is little to disagree with in this analysis, but there is a point to be made a bit more strongly: If McCain is to run as a conservative reformer, then serious tax reform is an issue he cannot duck. The tax code must rank high in any list of the dysfunctional institutions in American life. Yet tax reform would present McCain with a series of challenges.

The first is that he cannot simply repackage his existing tax-policy proposals as a reform. Those proposals are, in the main, worthwhile. Cutting the corporate tax rate to be more in line with the rates of other developed nations would promote growth. So would making the Bush tax cuts on dividends, capital gains, and estates permanent. Abolishing the Alternative Minimum Tax (AMT) would simplify the tax code. Doubling the dependent exemption would modestly reduce the antifamily bias of existing federal policies.

But that is a hodgepodge of nice ideas, not a coherent reform. It ties McCain too closely to Bush and the policy debates of the last eight years. It does not offer enough to the lower middle class voters McCain needs. And it is unrealistic, given current budget projections.

The McCain campaign appears to recognize the inadequacy of its platform on taxes. McCain has said that he will outline a bigger reform at some point this year. From what he has said, it does not sound as though he is going to push for a flat tax or a national sales tax. That's a good thing: Either of these conservative hobbyhorses would raise taxes on a lot of lower middle class families.

A Tax Trap

McCain's website says that he will propose a new, alternative tax system, adding, "When this reform is enacted, all who wish to stay under the current system could still do so, but everyone else could choose a vastly less complicated system with two tax rates and a generous standard deduction."

That makes it sound as though McCain is planning to go with some version of the tax-reform proposal that such conservative stalwarts as Rep. Paul Ryan, former presidential candidate Fred Thompson, and the Republican Study Committee have been promoting over the last year. That proposal has many good points. It brings the top tax rate way down to 25 percent (from the current 35).