For most of the past 20 years I have served on selection committees for the Rhodes Scholarship. In general, the experience is an annual reminder of the tremendous promise of America's next generation. We interview the best graduates of U.S. universities for one of the most prestigious honors that can be bestowed on young scholars.

I have, however, become increasingly concerned in recent years - not about the talent of the applicants but about the education American universities are providing. Even from America's great liberal arts colleges, transcripts reflect an undergraduate specialization that would have been unthinkably narrow just a generation ago.

As a result, high-achieving students seem less able to grapple with issues that require them to think across disciplines or reflect on difficult questions about what matters and why.

Unlike many graduate fellowships, the Rhodes seeks leaders who will "fight the world's fight." They must be more than mere bookworms. We are looking for students who wonder, students who are reading widely, students of passion who are driven to make a difference in the lives of those around them and in the broader world through enlightened and effective leadership. The undergraduate education they are receiving seems less and less suited to that purpose.

An outstanding biochemistry major wants to be a doctor and supports the president's health-care bill but doesn't really know why. A student who started a chapter of Global Zero at his university hasn't really thought about whether a world in which great powers have divested themselves of nuclear weapons would be more stable or less so, or whether nuclear deterrence can ever be moral. A young service academy cadet who is likely to be serving in a war zone within the year believes there are things worth dying for but doesn't seem to have thought much about what is worth killing for. A student who wants to study comparative government doesn't seem to know much about the important features and limitations of America's Constitution.

When asked what are the important things for a leader to be able to do, one young applicant described some techniques and personal characteristics to manage a group and get a job done. Nowhere in her answer did she give any hint of understanding that leaders decide what job should be done. Leaders set agendas.

I wish I could say that this is a single, anomalous group of students, but the trend is unmistakable. Our great universities seem to have redefined what it means to be an exceptional student. They are producing top students who have given very little thought to matters beyond their impressive grasp of an intense area of study.

This narrowing has resulted in a curiously unprepared and superficial pre-professionalism.

Perhaps our universities have yielded to the pressure of parents who pay high tuition and expect students, above all else, to be prepared for the jobs they will try to secure after graduation. As a parent of two teenagers I can understand that expectation.

Perhaps faculty members are themselves more narrowly specialized because of pressure to publish original work in ever more obscure journals.

I detect no lack of seriousness or ambition in these students. They believe they are exceptionally well-educated. They have jumped expertly through every hoop put in front of them to be the top of their classes in our country's best universities, and they have been lavishly praised for doing so. They seem so surprised when asked simple direct questions that they have never considered.

We are blessed to live in a country that values education. Many of our young people spend four years getting very expensive college degrees. But our universities fail them and the nation if they continue to graduate students with expertise in biochemistry, mathematics or history without teaching them to think about what problems are important and why.

The writer represented New Mexico in the U.S. House from 1997 to 2008. She is a graduate of the Air Force Academy and a Rhodes scholar.