Sens. Barack Obama and Hillary Clinton should stop beating up on each other in the remaining Democratic contests and focus their ire on the presumptive Republican presidential nominee, George McGovern said Tuesday.

In a letter published in the New York Times and at a news conference in Sioux Falls, the former Democratic senator from South Dakota and 1972 presidential nominee outlined what he called a formula to unify the party and defeat Sen. John McCain.

"We can reduce the danger of Sen. Clinton and Sen. Obama criticizing each other for the next month and giving McCain a free ride," said McGovern, 85.

"They are constantly pointing out weaknesses in the opposing candidate, which is what politicians do when they run for office. You can't blame them for that. But meanwhile, McCain is free to go around the country talking about motherhood and the flag and all those non-controversial things and looking like a statesman who is above the hurly-burly of politics."

McGovern's proposal is for Obama, the front runner, and Clinton to appear together at least once in each of the five remaining primaries in Kentucky, Oregon, Puerto Rico, Montana and South Dakota. The plan also could be used in Michigan and Florida if the party reconsiders its decision not to count those states' delegates, he said.

Instead of condemning each other, each candidate would speak for 15 to 20 minutes about what he or she would do if elected and then talk about why President Bush's policies have failed and why they would continue to fail under McCain, especially regarding tax cuts and the war in Iraq, McGovern said.

After the speeches they would go to the largest public place in town for a reception that would cost each attendee a $50 donation to the state parties, which are strapped because of the high cost of campaigns.

"So you capitalize on the popularity of these two great candidates. And I think they are great candidates. I like both of these candidates. That's why I endorsed Hillary in October and Barack in May. I've got 'em both covered now," McGovern said.

"We'd go into that convention more united than we have been in years," he said of the party's August gathering in Denver.

McGovern said he developed the idea out of his own experience in 1972 when he won California's largesse of delegates but the party split them proportionately between the candidates instead of abiding by the winner-take-all tradition.

"That was totally unfair," he said.

Instead of choosing a running-mate and planning the convention, McGovern said he spent the time fighting to get back those delegates. He lost that November to Republican incumbent Richard Nixon, winning only Massachusetts.

McGovern said he doesn't want a divided party to create a similar scenario for Obama and Clinton.

"One of them is going to lose and this would send them out in harmony and place the party and country's interests above their own," he said.

McGovern said former Senate Majority Leader Tom Daschle of South Dakota with the Obama campaign and Terry McAuliffe with Clinton responded favorably when he told them about the proposal.

Jack Billion, chairman of the South Dakota Democratic Party said, "I think it would be a very positive thing."

An Obama campaign official said Tuesday afternoon there have been no talks between the campaigns about joint appearances.

"Senator McGovern is a beloved leader in South Dakota and the Democratic Party. We are thrilled to have his support and look forward to competing for every vote and delegate in South Dakota," Obama spokesman Matthew Lehrich said in an e-mail.

Jeff Sadosky, a McCain campaign spokesman, said regardless of who wins the Democratic nomination, "their nominee will have promised dramatic tax and spending increases that will hurt our economy and take money from American middle class families.

"This election is about change, but we need a candidate with toughness, credibility and judgment to bring about the right change needed to get our economy back on track," he said in an e-mail.

Brendan Gilfillan of the Clinton campaign said McGovern's idea is something his candidate would consider. "Senator McGovern and Senator Clinton are old friends. He's put forward an interesting proposal, and we would certainly consider it," Gilfillan said.