WASHINGTON — This is what the power of one can look like in the U.S. Senate.

Sixty-eight senators, fully two-thirds of the chamber, Democrats and Republicans, are supporting legislation to expand research into the environmental causes of breast cancer.

But one Republican senator is blocking the bill from a vote.

Perhaps because so many lives have been touched by breast cancer, and everyone seems to know someone who sports a pink ribbon or has participated in a breast cancer awareness walk, the bill is popular. Each year, 250,000 women are diagnosed with the disease, and 40,000 women die. Doctors know neither the cause nor cure.

Senate Majority Leader Harry Reid attempted to bring the bill to the floor last week — a gesture, it seemed, after he arrived at work that Monday morning to learn a longtime former aide had been diagnosed with breast cancer and had died over the weekend.

The bill, versions of which have been around since 2000, would authorize $40 million over the next several years for the National Institutes of Health to investigate whether breast cancer is linked to something in the environment.

Oklahoma Sen. Tom Coburn, one of the chambers most conservative Republicans, objected.

Coburn is famous for exercising his power as a minority of one. Senate rules give members broad authority to hold up legislation, and Coburn uses his frequently to further his causes.

Coburn mostly fights earmarks — those special funding requests he believes are excessive government spending. Earlier this year, he held up a popular, bipartisan public lands bill that included a land transfer for the Southern Nevada National Guard Depot, until Reid worked around him.
Reid has powers, as majority leader, to force a procedural vote, or he can work with Republican leadership on a deal to bring bills forward. The lands bill passed the House yesterday and is on the way for Bush’s signature.

But all those maneuvers require valuable time. On a popular bill, the majority leader hopes to achieve unanimous consent to proceed.

Last night, Reid tried again to move the breast cancer bill.

Reid offered to hold a floor debate to amend objectionable parts of the bill. Coburn declined.

Coburn relied on his credentials as a medical doctor and as a fiscal conservative to make his case. He questioned why breast cancer should cut in front of other diseases needing research funds. He said scientists, not senators, should be deciding how to spend precious research dollars. He said $100 million is already being spent on similar research.

Republican leadership cannot, or will not, rein Coburn in.

Reid countered that senators have a responsibility to step in and shape policy. Women’s health has suffered under a male-dominated Senate, and is only now starting to receive the attention it deserves as more women are elected to the chamber, added another Democratic senator, Maria Cantwell of Washington.

Coburn was unmoved. “Every time this bill comes to the floor, I will object,” he said.

And he did.