An effort to make the Homeland Security Department more accountable for the billions of dollars it hands out in grants faltered Tuesday in the Senate as lawmakers wound up work on a broad antiterrorism bill.

The Senate rejected amendments by Sen. Tom Coburn, R-Okla., that would end many of the grants in five years and condition funding of them in the interim on the department doing a better job of tracking the money.

"Here's a tool to force Homeland Security to manage its money, to hold them accountable," he said, "by cutting of that money. This is tough love."

Coburn's measures, however, died on 60-38 and 66-31 votes after the bill's sponsors, Sens. Joe Lieberman, I-Conn., and Susan Collins, R-Maine, argued they would disrupt the flow of badly needed security funding to the states.

A final vote on the bill was expected later Tuesday, but its fate is far from certain because of language that would give union bargaining rights to 45,000 federal airport screeners.

The House has already approved the bargaining rights, and the Senate did so in a more limited form, but a threatened veto from President Bush will force congressional negotiators to review the collective bargaining issue again when they try to negotiate a compromise version of the two bills.

The competing versions differ in many respects but both call for enacting several previously rjected recommendations of the bipartisan commission that investigated the terrorist attacks of Sept. 11, 2001.

One significant difference is the way homeland security money is divvied up among the states. The House bill is more to the liking of the Bush administration, because a greater amount of the spending would be based on risks and vulnerabilities.

The House version is also more in line with the 9/11 commission's final report, which concluded that "homeland security assistance should be based strictly on an assessment of risks and vulnerabilities," adding that "Congress should not use this money as a pork barrel."

The Senate version would allow a larger amount of funds to be divided equally among states to ensure that all localities have certain basic capabilities to respond to any emergency, whether natural or caused by man.

The House assigned no price-tag to its bill, but the Senate version calls for a total of $3.1 billion in spending for grant programs for each of the next three years. Of that, $1.3 billion is specified for high-risk urban areas.

Both bills provide money to state and local emergency responders to improve emergency communication systems. The House bill again had no price-tag, but the Senate would authorize $3.3 billion over five years.

The House and Senate bills also differ on how to deal with cargo containers that could hold a nuclear bomb or a so-called dirty bomb using conventional explosives to spread radiation. The House bill calls for radiation screening in foreign ports of all U.S.-bound cargo containers within five years. The Senate rejected a similar measure and the White House says it would be too costly and would slow commerce to a crawl.

The House bill also would require 100 percent screening for explosives of all cargo loaded onto passenger aircraft. The Senate gives airport screeners more flexibility.

Despite several amendments that still required votes Tuesday, Senate leaders predicted easy passage for the bill. The one looming controversy that remains is that of union rights for Transportation Security Administration screeners.

Both bills also provide whistleblower and collective bargaining rights to 45,000 airport screeners whose jobs were federalized when the Home Security Department was created in response to the Sept. 11, 2001 terrorist attacks. Congress forbade collective bargaining for them then and Republicans boast they have the votes to uphold a veto by Bush over the issue.