With that, the Nevada Republican is siding with the president in a looming spending battle. Bush has demanded lawmakers approve $108 billion for operations in Iraq and Afghanistan but nothing more for other priorities.

While planning to provide financial support for U.S. troops, Senate Majority Leader Harry Reid and fellow Democrats also are considering billions of dollars for road construction and repairs and other economic stimuli.

Reid backs federal aid to the health district. He said Thursday that "it is not going to make it any easier" to obtain the funding if Ensign is not on board.

Ensign said in a separate interview, "We are trying to keep the supplemental bill clean. We are looking to do this in a responsible way."

He added: "You start adding things, you know what happens. It becomes a Christmas tree."

Ensign said he has asked the Department of Health and Human Services to find money in its budget that could be directed to Las Vegas so that Congress would not have to spend "and add to the deficit."

"These are huge agencies," Ensign said. "There is money out there that is unspent."

He has received no response yet from the department.

Ensign's position is consistent with his reputation as a fiscal conservative. But on the matter of the massive health alert that has hit close to home, his stance was criticized Thursday.

Rep. Shelley Berkley, D-Nev., said the local funding "should not be held hostage by political gamesmanship."

"It is more than appropriate to make this request part of a funding package designed to address emergencies and other pressing needs including funding for our troops," Berkley said in a statement. "While others may want to sit on their hands, I am not willing to wait another nine months or longer for these funds."

It's not clear when, or if, lawmakers will consider other appropriations bills before the fall elections.

Rep. Jon Porter, R-Nev., supports adding Las Vegas health funding to the war spending bill, spokesman Matt Leffingwell said.

But Porter's vote will depend on how the bill addresses Iraq, Leffingwell said. If Democrats add troop withdrawal provisions, for instance, Porter would vote against it.

Aides to Rep. Dean Heller, R-Nev., did not respond to a message seeking his views.

Signs of Ensign's reluctance to back the Las Vegas spending surfaced earlier this week when he did not join Reid in recommending it to the Senate Appropriations Committee.

In response to a Reid invitation, officials from the Southern Nevada Health District asked for $3 million to pay for the blood tests of 15,000 uninsured and under-insured people who were patients at the Endoscopy Center of Southern Nevada.

Another $1.4 million was requested for follow-up testing and vaccinations for persons who test positive for HIV or hepatitis.

Nearly seven weeks ago, 40,000 letters were sent to former patients of the Endoscopy Center of Southern Nevada by health care authorities because of unsafe injection practices at the clinic. The patients were urged to be tested for blood-borne diseases, including hepatitis C, an incurable, potentially fatal condition that attacks the liver.

Other funds would support the health district's hepatitis help line and pay to organize patient records seized by authorities during searches of the endoscopy center and its sister facilities in the valley.

Reid also requested $21 million on behalf of the Centers for Disease Control and Prevention, the federal agency that has assisted Southern Nevada authorities.

Some of those funds would steer into the agency's work in Las Vegas, including genetic mapping to determine whether infections could be traced to problem clinics. Other funds would initiate awareness campaigns to avert future disease outbreaks caused by imprudent health procedures.

The agency also seeks $3.5 million to "incentivize" the private sector into fast-tracking research and development of safer medication packaging such as single-use-only syringes, according to officials who have seen the request.

For some of the proposed CDC programs, the new money would amount to a down payment. Congress would be asked to spend more to keep the projects going into future years.

Ensign said he had reservations about the agency's request. The CDC might have sensed an opening and built a wish list.

"I just don't want the CDC to pile on," he said. "I am looking into this more carefully."

Contact Stephens Washington Bureau Chief Steve Tetreault at stetreault@stephensmedia.com or 202-783-1760.