MITT ROMNEY’S contemptuous attitude toward the importance of public disclosure is increasingly troubling. Whether it involves the details of his personal finances or the identity of his big fundraisers, the presumptive Republican is setting a new, low bar for transparency — one that does not augur well for how the Romney White House would conduct itself if he were elected.

First is the matter of tax returns. Mr. Romney’s campaign, belatedly and under pressure, released a single year’s worth of tax information in January along with a summary for the 2011 return. Now, with a Friday afternoon release conveniently timed for minimum news coverage a week ago, it announced that the candidate had filed for an extension.