Less than 16 months out from Election Day, a handful of Senators make up what could be called the Undecided Caucus: five veterans unsure of whether they’ll run for re-election in 2004.

With their collective decisions having the potential to dramatically reshape the narrowly divided Senate, they consist of a pair of veterans doing enough to remain politically viable, an octogenarian who appears to be doing the bare minimum of fundraising, and a pair of would-be presidents who were placed in their own “special case” by their party leader.

Democrats face the most acute retirement problem in the months ahead, with one, Sen. Zell Miller (Ga.), having already announced his plans to step down next year and four more considering leaving the chamber.

From Kitty Hawk to Key West, Democrats have a quartet of potentially retiring Senators on the lower half of the Eastern seaboard, all states where President Bush remains popular. A fifth potential vacancy could come in another so-called “red state,” Louisiana, if Sen. John Breaux (D) decides to move on after three terms in the chamber.

On the Republican side of the aisle, Sen. Don Nickles (Okla.) remains the only Senator still publicly contemplating whether to run for re-election.

The decisions of Breaux, 59, and Nickles, 54, are arguably the most important to each of their respective parties because they would both be overwhelming re-election favorites, but their retirements would instantly turn both seats into tossups.

Both men began positioning themselves to run for another term in the second quarter of the year, raising enough money to increase their already sizable campaign accounts — but not enough to end retirement talk.

Breaux said he would report having $1.4 million in his campaign account as of June 30, representing roughly $400,000 raised in the period and less than $100,000 spent. He ended the previous quarter with a little less than $1.1 million, according to reports with the Federal Election Commission.

Sticking to his previously stated timeline, Breaux said Wednesday: “I’m raising money. I’m preparing to run. And I’ll make a decision after the November elections in Louisiana,” when the state will choose a new governor.

Nickles raised $336,000 in the quarter, according to the Oklahoman’s aides. Combined with $438,000 he had in the account March 31, Nickles pushed his current cash-on-hand total into the $700,000 neighborhood.

Nickles, whose 14-year run in various Senate leadership posts ended last year, has said he may wait as late as next spring to decide if he’ll run for re-election. He focused the past few months on raising money for his campaign committee, trying to dampen some of the talk about his intentions.

“While Senator Nickles has not made a decision, he is taking action to make sure he is well-positioned should he decide to run,” said Brook Simmons, director of legislative affairs and communication for Nickles.

Breaux has stuck to a steady diet of a fundraising “lunch or two a week,” according to one strategist, with plans to increase the pace of those events in the months ahead. Nickles, who is now Budget chairman, has had two large-scale fundraisers. The first, a May 6 reception and dinner at the National Republican Senatorial Committee, focused on the corporate PAC community. According to FEC filings, corporate political action committees pumped $123,000 into Nickles’ campaign in late April and May.

The second, June 16 in Oklahoma City, brought in about a third of Nickles’ total fundraising haul for the quarter.

Sen. Fritz Hollings (D-S.C.), on the other hand, does not appear to have done nearly as much political work as either Breaux or Nickles, placing his future in an even more uncertain state: Unlike Breaux or Nickles, Hollings can expect a vigorous challenge even if he decides to run for a seventh full term.

Hollings’ allies could point to just one fundraiser in the second quarter, his annual barbecue event early last month in the District. While his aides would not release Hollings’ FEC numbers before the July 15 reporting deadline, the barbecue event usually pulls in close to $100,000. In the first quarter of the year, Hollings raised just $6,000 but still had a respectable $912,000 on hand.

Still, Democrats have privately grown very doubtful about the chances of Hollings running for re-election, particularly after he authorized Palmetto State Democrats to begin recruiting potential successors in anticipation of his retirement.

Senate Minority Leader Tom Daschle (D-S.D.) said Wednesday that he expects a decision from them in the fall. “My expectation is that most, if not all, of those who have yet to make that announcement or that decision will decide to run for re-election,” he said.

Daschle quickly acknowledged that two other potential retirees, Sens. John Edwards (D-N.C.) and Bob Graham (D-Fla.), were their own “special case” because both are running for president. He took pains to try to avoid putting any public pressure on the White House aspirants’ Senatorial intentions, but admitted that public decisions would help line up potential candidates to defend those seats if either, or both, decided against running for reelection even if their presidential campaigns crashed.

“They’re a special case because they have the matter of a presidential candidacy,” Daschle said. “And I say that I’ve not pressed them for a time — obviously the sooner we would know their intentions, the better.”

“I’m sure that in due time, we will be in a position to know more,” he added.

A Graham retirement could on its own put the Senate Democrats in an even more precarious position than they already face, with 19 of the 34 seats up for grabs being held by Democrats. As a popular former two-term governor, Graham could coast to re-election and spare the Democratic Senatorial Campaign Committee from devoting any resources to the expensive state.

Despite Graham’s public admonitions that he intends to run solely for the White House, some Democrats have privately said that, should his presidential campaign falter, they expect him to run for another term.

With midterm fundraising reports trickling in, Graham appears to be in sixth place in terms of dollars raised among the nine Democrats currently running for the White House. He has until late May 2004 to file to run for the Senate.

In North Carolina, there is likely to be a bruising Senate race with or without Edwards. Rep. Richard Burr (R-N.C.) appears to have the GOP nomination to his own, and he expects to have more than $3 million in the bank.

And Edwards’ campaign for president has been an issue in the Senate campaign. “Every day that Senator Edwards runs for president is another reminder that he’d rather not be the Senator from North Carolina,” said Sen. George Allen (Va.), chairman of the NRSC.

Edwards has proven to be an enigmatic presidential campaigner, raising more than $12 million, second in the field so far, but remaining in single digits in polling in key states. He has until late February to file to run for re-election, but most observers believe a decision must be made by the fall in order to give potential successors, including former White House Chief of Staff Erskine Bowles, time to raise money and build a campaign.

Edwards’ most recent statement on the issue, given to reporters trailing him on the North Carolina beaches over the July 4th holiday, was that a decision on running for the Senate would be based on “what the dynamic is in the presidential campaign.”

Edwards has $1.4 million still sitting in a Senate campaign account.

But those decisions will have to wait for another day, as Daschle noted of Graham and Edwards on Wednesday — in one breath calling it “appropriate” for a decision before the end of the year and in the next urging restraint.

“I’ve tried to be as sympathetic and empathetic with their circumstances and have not pressed them for a particular indication of what their time frame will be,” he said.