With rumors once again swirling that

Robert Rubin

is on his way out the door, the odds-on favorite to fill the boyish, politically savvy

Treasury

secretary's shoes is his deputy,

Lawrence Summers

.

"Summers is far ahead as a front-runner," says Allen Jacobson, economist and senior vice president of

HSBC Washington Analysis

, a political analysis firm. "He and Rubin get along extremely well, and Rubin is the president's favorite. So if Rubin wants Summers

as a successor, there's really not anyone else."

Still, questions about some administration decisions in which Summers has been a driving force make his ascension less than an absolute certainty, as does the deputy's prickly personality. And there are at least a couple of Democratic stalwarts who might get the nod should a Summers nomination fail.

'Like Batman and Robin'

The 44-year-old Summers, who at 28 became

Harvard's

youngest Ph.D. to receive tenure as a professor, played a leading role in financial-rescue plans for Mexico, Russia and countries in Asia.

"Those two are like Batman and Robin" in terms of working on ideas, says Jacobson. "Rubin gets a lot of ideas from Summers, who acts as a sort of

brain trust at Treasury on issues such as Social Security, Japan's need for fiscal belt-tightening and possibly forcing the Japanese central bank's hand to monetize their debt."

It's an open secret that Rubin hopes his deputy gets the nod to follow through on Treasury's key initiatives, political analysts say. Among those goals are maintaining a strong dollar, supporting the

International Monetary Fund

and fostering open, stable international markets. At a press conference in New York Wednesday, Rubin said he "didn't want to comment" on a potential successor.

President Clinton

named Rubin the 70th Treasury secretary in 1995. A former

Goldman Sachs

co-chairman, Rubin has earned praise from Democrats and Republicans alike, as well as from Wall Street.

'Not Going to Be There Much Longer'

Though Rubin is in good health, his wife reportedly has never liked Washington and few believe the 60-year-old Treasury chief wants to stay on until Clinton leaves office. "Rubin is not going to be there much longer," says Jacobson.

If he wants to leave, "the pressure would be on for him to do it sooner rather than later," says one Washington economist. "The market is calm right now; we're over the hump in emerging markets like Brazil."

But Summers' confirmation by

Congress

is not a sure thing. After Summers joined the

World Bank

in 1991 as its chief economist, he played a key role in designing the lending agency's assistance programs for some of the same countries that now find themselves enmeshed in a global crisis.

While widely recognized as brilliant, "he's rubbed a lot of people the wrong way," says Dean Baker, a senior research fellow at the

Preamble Center

and

Century Foundation

think tanks.

Summers "is a very brash character, and sometimes acts like people don't know what they're talking about," Baker adds. Moreover, Summers may have a difficult time justifying Treasury's support for the disastrous IMF bailout of Russia last summer to the Republican majority in Congress.

"Summers can be somewhat arrogant," says Cynthia Latta, principal economist with the

DRI/McGraw-Hill

forecasting firm in Lexington, Mass. "People in Congress don't like other people who are also arrogant."

Also in the Wings: Raines and Johnson

Who else, then, is a potential candidate for the key Treasury-secretary spot?

Two names surface consistently, although they are viewed as distant runners-up.

Franklin Raines

, head of

Fannie Mae

(FNM)

, tops the list. Raines could easily appease the Republicans: His basic views wouldn't be very different from those of Summers, but "he'd probably present it to Congress in a more populist way," adds Jacobson. Raines has presided over Fannie Mae during a boom in house building and buying, low interest rates and easily refinanced mortgages.

Raines, who served as Fannie Mae's vice chairman from 1991 to 1996, returned to the company Jan. 1 as chairman and CEO after serving in the interim as director of the

Office of Management and Budget

and a member of Clinton's cabinet. Raines was Clinton's key negotiator in the talks that led to passage of the balanced budget act in 1997. Raines cut his Wall Street teeth during 11 years as a

Lazard Freres

general partner.

Third in line is

James Johnson

, Raines' former boss at Fannie Mae.

The ultimate Washington insider, Johnson has worked for no fewer than five failed presidential campaigns -- his last as chairman of the disastrous effort that ended in

Walter Mondale's

49-state loss to

Ronald Reagan

.

After quietly pursuing a lucrative career in business, the 54-year-old Johnson became Fannie Mae's chairman, before handing the mantle to Raines.

Johnson is chairman of the

Brookings Institution

and of the capital's mammoth performing-arts jewel, the

Kennedy Center

.

"He has exactly the sort of Washington Democrat resume who would be a natural under Gore," were the vice president to prevail in the 2000 presidential elections, says the Washington economist.