Being a politician requires certain skills and talent, like any human activity. Merely understanding policy options is just one useful talent for a politician, but not even a necessary one.
One of the most effective local politic ans I ever covered as a town report was a man who had been a town selectman for close to three decades. He was not the brightest bulb who ever sat in a chair of power. He really had only the most rudimentary grasp of things like the town budget.
But he understood people very well, and had little trouble winning re-election year after year because he knew that he was ultimately in a people business and he could hire people who understood the budget. By the same token, I've seen a lot of people who had a very good grasp of the mechanics of government yet no ability to get people to work together.
Politicians at the level of Barack Obama, Hillary Clinton and John McCain, of course, must have some ability to handle all the aspects of being a leader. Despite their reputations, for example, neither Ronald Reagan nor George W. Bush were/are unintelligent.
But talents are unevenly distributed and the long campaign has already highlighted that Obama may be the best balanced leader among the final three. Whether that means he will be a success as president remains to be seen. Sometimes the times a president finds himself in my require character that is particularly strong on one way or another and not balanced.
Hillary Clinton seems to understand policy very well, but one is still left with the feeling she doesn't understand people as well. Her husband was famously a people-person, but she has to work at it. Her relationship with her staff suggests a person who has to manage explicitly rather than instinctively.
McCain, on the other hand, is very much a people person, but seems to have a weak grasp of policy issues. Even in areas where he imagines himself to have expertise he seems spotty with his positions taken on "gut" rather than analysis.
Watching Obama and Clinton perform their little Unity dance at Unity, N.H., is a reminder that purity and uncompromising principles are all very well for pundits and professors, but totally unsuitable for a politician. If one could imagine little thought balloons over their heads the words would undoubtedly belie their public presentation.
But politic ans have to have the discipline to set aside their feelings for the larger goals they are pursuing and this is not inappropriate. We see the same things in other fields and think nothing of it. Medical personnel are faced with horrific sights all the time yet maintain a professional demeanor as they provide care.