The attendance of four Democratic Senators running to take on President Bush in 2004 could make or break a number of key Democratic-sponsored amendments to a fiscal 2004 labor, health and education spending bill this week.

“We’ll do everything we can to ensure all of our votes are here,” Sen. Tom Harkin (D-Iowa) said in reference to Sens. John Kerry (Mass.), Joe Lieberman (Conn.), John Edwards (N.C.) and Bob Graham (Fla.).

Harkin is sponsoring an amendment to prevent the Bush administration from implementing new employee overtime rules that, according to Democrats, would disqualify as many as 8 million workers from getting extra pay when they work more than 40 hours a week.

Harkin, who announced his intentions Tuesday, unofficially kicked off what is expected to be a Democratic onslaught of amendments to the $464 billion Labor, Health and Human Services, and Education appropriations bill, which funds nearly all of the signature Democratic issues on public schools, college education, health care and worker protections.

Without the four presidential contenders in the chamber, Democrats may have only 45 votes to work with — or 44, if one accounts for the fact that Sen. Zell Miller (D-Ga.) usually sides with Republicans. That means Democrats would need to get seven GOP votes, rather than the usual two or three, to prevail.

“It’s difficult to win without five votes, but they’ve generally been pretty cooperative,” noted a Democratic leadership aide. “We’re always in close contact with them, letting them know what votes are coming up and when we’ll need them.”

Aides to the candidates said they will do everything possible to make the votes, but Republicans could force immediate votes with a “motion to table.”

Just as Harkin is counting on Democratic presidential candidates (as well as GOP moderates) to give him the necessary 50 votes to prevail, so too are other Democrats. Their amendments to the appropriations bill include increasing public education funding, beefing up federal Pell Grants for college, boosting funds for special education and improving health care funding in a variety of ways.

Adoption of any of those proposals this week or next could deal a serious blow to the Bush administration and Republican leaders in Congress, while giving a much-needed boost to Democrats who have seen President Bush’s approval ratings continue to remain high.

However, the success of the education proposals in particular are likely to be hampered by Democratic presidential candidate schedules, because most of those votes are expected this week.

Most of the Senatorial presidential candidates are touring in other parts of the country this week, making it more unlikely they will be able to make those key education votes. They all have a debate scheduled this Thursday in New Mexico, for example.

Senate GOP leaders, meanwhile, are obviously not inclined to hold off on votes until the four presidential candidates can be present.

“The Senate has important business to attend to, and we’re going to move ahead on the Labor-HHS and do the work we have to do,” said Amy Call, a spokeswoman for Senate Majority Leader Bill Frist (R-Tenn.).

Harkin may be in more luck, because he wants to wait to hold a vote on the overtime pay issue until next week. He could see success then on either Tuesday or Wednesday of next week, when the four presidential candidates are likely to be in the Washington area attending a service employee union event as well as a Baltimore, Md., debate sponsored by the Congressional Black Caucus.

Harkin counts between three and six Republican supporters of his amendment. Likely GOP suspects include labor supporters Sen. Lincoln Chafee (R.I.) and the bill’s floor manger, Sen. Arlen Specter (Pa).

The GOP leadership has not yet determined whether it has enough votes to defeat Harkin’s proposal, according to Call.

Harkin’s proposal still would allow the department to implement another part of the proposed rules which would allow people making up to $22,100 a year eligible for overtime. The current cap is around $8,000 per year, and the Bush administration has pushed the proposal by saying it would make 1.3 million lower-income people eligible for overtime pay.

Even if Harkin succeeds in adding his proposal to the bill, the White House has promised to veto any bill that contains such a provision.