WASHINGTON -- Cindy McCain says she will never make her tax returns public even if her husband wins the White House and she becomes the first lady.

"You know, my husband and I have been married 28 years and we have filed separate tax returns for 28 years. This is a privacy issue. My husband is the candidate," Cindy McCain, wife of Republican presidential nominee-in-waiting John McCain, said in an interview aired on NBC's "Today" on Thursday.

Asked if she would release her tax returns if she becomes first lady, Cindy McCain said: "No."

The Arizona senator released his tax return last month, reporting he had a total income of $405,409 in 2007 and paid $84,460 in federal income taxes. He files his return separately from his wife, an heiress to a Phoenix-based beer distributing company whose fortune is in the $100 million range.

Sen. McCain is routinely ranked among the richest lawmakers in Congress, but he and his wife have kept their finances separate throughout their marriage. A prenuptial agreement left much of the family's assets in Cindy McCain's name. Democratic National Committee Chairman Howard Dean said Cindy McCain's refusal to release her tax returns gives the appearance of a double standard on the part of her husband.

"What is John McCain trying to hide?" Dean said in a statement. "Throughout this campaign, he has acted like his own calls for openness and accountability apply to everyone but himself. Now he thinks he can bring that same double standard to the White House."

In response, Republican National Committee spokesman Danny Diaz said, "Howard Dean continues to lower the bar in this election."

Democratic presidential candidates Sens. Barack Obama and Hillary Rodham Clinton filed joint tax returns with their spouses and publicly released those returns.

The McCains' marriage has mixed business and politics from the beginning, according to an expansive review by The Associated Press published in April of thousands of pages of campaign, personal finance, real estate and property records nationwide.

As heiress to her father's stake in Hensley & Co. of Phoenix, Cindy McCain is an executive whose worth may exceed $100 million, and beverage industry analysts estimate Hensley's value at more than $250 million, with annual sales of $300 million or more. Hensley describes itself as the third-largest Anheuser-Bush wholesaler in the United States.

• Within a few years of marrying Cindy Hensley, the daughter of a multimillionaire Anheuser-Busch distributor, John McCain won his first election. He was new to Arizona politics and fundraising in the 1982 House race, and his campaign quickly fell into debt. Personal money -- tens of thousands of dollars in loans to his campaign from McCain bank accounts -- helped him survive.
• Anheuser-Busch's political action committee was among McCain's earliest donors. Cindy McCain's father, James Hensley, and other Hensley & Co. executives gave so much the Federal Election Commission ordered McCain to give some of it back. McCain's campaign used Hensley office equipment such as computers and copiers, and Cindy McCain personally paid some of the campaign's bills.
• Hensley executives are among the Arizona senator's top career givers. The Anheuser-Busch PAC has given McCain's campaigns at least $19,500 over the years. McCain's campaign fundraisers include Robert Delgado, Hensley's president and chief executive officer; Andrew McCain, the company's chief financial officer and John McCain's stepson from his first marriage, to Carol Shepp; and August Busch III, chairman of Anheuser-Busch's executive committee. Anheuser-Busch in 2006 gave $25,000 to the International Republican Institute, a pro-democracy group chaired by McCain.

The National Beer Wholesalers Association political action committee doles out millions of dollars to Democratic and Republican congressional candidates each election. John McCain's campaigns have received at least $26,000 from the association over the years. An informal poll on the trade group's Web site asks visitors which presidential candidate they would most like to have a beer with (Democrat Barack Obama was way ahead in late March with 45 percent; McCain was second, with 23 percent). The connection to McCain hasn't helped the beer lobby in Congress, AP reported.

• McCain has long said he refrains from voting on beer industry-specific issues. Following that policy, McCain voted "present" when the Senate voted in March 1998 to withhold state highway funding from states that failed to adopt a .08 blood-alcohol standard for drunken driving.
• Two years later, McCain voted against the fiscal 2001 transportation appropriations bill, which set a national .08 standard. The National Beer Wholesalers Association opposed the legislation and told its members it had at least succeeded in "delaying and diluting the final version." McCain voted against the bill because he objected to "pork-barrel spending," Hazelbaker said.
• Beer wholesalers and other businesses tried unsuccessfully to block a campaign finance law that McCain co-sponsored banning corporate contributions to the national Democratic and Republican parties. On another top business issue, the estate tax, McCain has supported cuts but opposes permanent repeal. Beer wholesalers contend a repeal would help save family businesses like Hensley.