From the Wall Street Journal’s Washington Wire:

[John McCain’s] preferred tax solution is to let former Federal Reserve Chairman Alan Greenspan figure it out. “We need a fairer, flatter tax,” McCain said. To that end, he would create a tax reform commission headed by Greenspan similar to the commission that oversaw military base decommissioning.

McCain also weighed in on Mike Huckabee’s fair-tax plan:

[He] said he’d sign a fair-tax bill if it “came across my desk.” A national sales tax would be “better than the current tax system,” he said, but added that he has “significant problems with it” and “can not support it in its present form.” … [He] said his main beefs are over whether the “fair tax” plan’s 23% rate is high enough to create sufficient revenue. He also would want a national sales tax law accompanied by the repeal of the Constitution’s 16th Amendment, giving the federal government the power to collect incomes taxes.