The opposition to Graham's nomination may come in part from his critics' fears that his research uses scientific methods that are hard to combat but may be influenced by subtle value judgments that are not easily shown as being biased.

In a sense, this is an argument about where science stops and political value judgments begin. Both sides think they are right because they draw the line in different places-and do not acknowledge the validity of the others' position.

"John and I can argue endlessly on a problem-basically about where that line is," Evans says.

Risk analysis is a relatively new field of study which uses quantitative methods to make decisions about what rules and regulations would be the most effective for the least cost.

In some cases, it requires that researchers make some basic value judgments about what risks, to which people, are less serious than other risks. Such judgments, say critics of Graham and his center, are where the bias toward corporations arises and why they cast doubt on the scientific validity of his work.

"I think in a way, one of the major reasons [for the opposition] is that all of us connected with the Center favor formal, quantitative analysis," says Evans. "This analysis is not attractive to environmental groups because certain regulations are not cost effective."

Morgan, a registered Democrat, says he supports the integrity of Graham's work even while acknowledging that there are certain parts of risk analysis that cannot be done with purely scientific tools.