WASHINGTON -- Rep. Jim DeMint, a conservative Republican running for the Senate in South Carolina, will this week introduce a Social Security reform permitting private investment by younger workers. That's not unusual. What's unusual is his intended co-sponsor: Rep. Harold Ford Jr. of Tennessee, a rising Democrat superstar and Congressional Black Caucus member.

DeMint told me Ford shook his hand, looked him in the eye and said he was on board. Press releases prepared by the Republican refer to the "DeMint-Ford Social Security Savings Act." But two days of my telephone calls to the normally easily accessible Ford proved futile. Is Ford backing out? Or, is he just nervous about abandoning his party's monolithic opposition to Social Security remedies that they condemn as privatization?

If Ford goes through with his collaboration when DeMint's bill is unveiled this week, it will constitute a major breakthrough in efforts to save the Social Security system while transforming the lowest income Americans into investors. Such reforms came under withering though largely ineffective attack from Democrats in the 2002 campaign, and all of the party's 2004 presidential candidates oppose them. Ford would show the way to fellow Democrats to abandon partisanship on Social Security.

Sen. Lindsey Graham, another conservative Republican from South Carolina, earlier this year joined moderate, mainly Southern Democrats in proposing an end to attacks on anybody who wants to change the Social Security system. DeMint goes further, seeking to enlist a mainstream liberal Democrat in a specific reform.

Ford's co-sponsorship would undermine the Democratic mantra that there is nothing the matter with Social Security and that Republican warnings are really a plot to privatize this legacy of Franklin Roosevelt's New Deal. In fact, the non-partisan General Accounting Office estimates the system will go into deficit in 2017 and be bankrupt by 2041. DeMint and other Republican reformers seek to prevent that train wreck by permitting private investment rather than reducing benefits or increasing payroll taxes.

DeMint's plan is set apart from the others in two ways. First, it is progressive. It would permit the lowest paid Americans a higher percentage of investments. Persons making under $15,629 a year could invest 8 percentage points of the present 12.4 percent payroll taxes. Workers with less than $34,731 income could put in 7.1 percent. The progressive sliding scale would drop to 3 percent for people with over $87,000 income.

This dramatic opening of investment opportunity for all Americans to compensate for the country's demographic changes is no free lunch. According to the Social Security Administration's actuaries, transition costs of DeMint's plan would be $8.2 trillion over the next 75 years. But the same source estimates the 75-year-cost in higher taxes at $26.1 trillion if nothing is done. That's how DeMint claims his plan will save taxpayers $17.9 trillion.

DeMint's second unique aspect is Harold Ford. Since his election in 1996 at age 26 from the Memphis congressional district previously represented by his father, he has been marked as a party leader for the future. He has been talked about as a Senate candidate. After the 2002 election, he challenged Rep. Nancy Pelosi to be House Democratic leader. He is liberal but not ultra-liberal. As measured by the Americans for Democratic Action, his liberal voting record was 85 percent in 2001 and 70 percent in 2002.

Joining DeMint would be a daring act by Ford to show Democratic colleagues that Social Security need not be bound by the restraints of a 1938 economy and social structure. "I applaud Congressman Ford for his bold and courageous stand," DeMint told me. "He is a visionary congressman who understands the need to address the wealth gap in America."

But will he really go through with it this week? I have found Ford to be an amiable young politician with a sparkling personality who never has been averse to publicity. He knew why I was trying to contact him when he declined to talk to me. Harold Ford Jr. risks a lot this week as he decides whether to cast aside partisanship and to open the door of America's wealth to its poorest citizens.