WASHINGTON — To the long list of rich-guy foibles that turned into defining campaign moments — John Edwards’s $400 haircut, John Kerry’s kite-surfing, John McCain’s inability to remember how many homes he owns — let us now add Newt Gingrich’s $500,000 revolving line of credit at the luxury jeweler Tiffany & Company.

The way Mr. Gingrich sees it, as he said on “Face the Nation” on Sunday, he’s “a guy running for president who pays all of his bills,” who lives within his budget and who is in fact “very frugal.”

The way some voters out in the rest of America might see it, he’s a guy who paid more for jewelry than some people pay for their houses.

It has been a week since Politico broke the news that while working for the House Agriculture Committee, Mr. Gingrich’s wife, Callista, filed forms for 2005 and 2006 disclosing her husband’s “revolving charge” of $250,001 to $500,000 with Tiffany. Mr. Gingrich, insisting his jewelry buying habits are his own business, has declined to say what he bought.