WHEN Tom Coburn was elected to the U.S. Senate two years ago, he promised in a television ad: "What I say may not always be diplomatic, but it will always be the truth."

Coburn, R-Muskogee, has held true to that vow so we're not at all surprised by his refusal to let a breast cancer research bill be rubber-stamped in Congress. Rather, he deserves kudos for sticking by his principles and not overlooking this bill just because it's proven popular among his fellow senators.

At issue is a proposal to set aside $180 million to research potential environmental causes of breast cancer. Coburn, a doctor, told The Oklahoman that the research being sought is already being conducted. He said $600 million a year already is being spent on breast cancer research and that the National Institutes of Health is spending $100 million.

The senator, himself a cancer survivor, noted his sister and sister-in-law had breast cancer. And we have no doubt that as a physician, Coburn appreciates the value of federally funded research.

But Coburn said politics, not science, is behind the support for the new research money. We're inclined to agree. The NIH, Centers for Disease Control and Prevention and other publicly funded medical research groups are capable of figuring out how to best spend the millions in government dollars they receive every year. They don't need Congress telling them what specific areas to research. That should be determined by scientists who are experts in their field, making their case before fellow scientists.

Oklahomans voted to send Coburn to Washington, believing in his promise that he would serve based on principles. He's put those principles into practice time and again over the last two years — a quality we could use in more of our public officials. No doubt we can expect more of the same in the years to come, even if it lands Coburn in the unpopular crowd.