On the night before the Pennsylvania primary, I was driving home from Pittsburgh, listening to NPR, thinking that I would vote the next day for Sen. Hillary Clinton.

At the University of Pittsburgh, where I had just taught a class, Sen. Barack Obama's campaign was staging a stadium-sized rally at the Petersen Events Center. I had thought of going until the parking attendants at the Soldiers and Sailors garage told me there was a line two blocks long waiting to get in and that the candidate would be late in arriving from McKeesport.

So I began my hour-long commute to Grove City, reflecting on the energy I had felt on the Pitt campus as people headed toward the Obama rally. After seven weeks of paying attention to the acrimonious campaign for the hearts and minds of Pennsylvania Democrats, I was becoming annoyed at Mrs. Clinton's constant attack mode and frustrated by Mr. Obama's tendency to blunder -- the latest being his comments on bitter small-town people clinging to religion and guns.

I had clung to Mrs. Clinton, whose candidacy I had supported since the New Hampshire primary when she seemed to share with us some of the emotions behind her commitment to seeking the presidency. I liked her health-care plan because I have one of those conditions that insurance companies won't insure, having experienced an insurance company deciding not to pay for a cancer operation because it would remove only the cancer rather than an entire organ. I went ahead with the surgery, which appears to have been successful, and was able to get the insurance company to pay for the procedure after spending weeks preparing my appeal.

Mrs. Clinton gained my support because she had addressed my medical issues. Health care was her hallmark. Experience was her byword. Harry Truman was her style. Yet she was wearing me out. She sounded shrill as she pounced on Mr. Obama's supposed elitism. She had a way of nodding in agreement with herself that I linked to her husband's way of wagging his finger to make a point. Both gestures seemed self-righteous.

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I am a Caucasian male, 62, not "working class" in terms of blue collar but not a member of an elite unless you count the well-educated impoverished. By turns I had been a journalist, communications director for schools and colleges, and college teacher of the academic gypsy variety. I was -- and am -- struggling to get by.

I had read that people like me were proving to be a tough sell for Mr. Obama. Yet that energy in Oakland as the loyal and the curious crossed Fifth Avenue to climb the hill toward the Petersen Center had resonated with me. Was it the mysterious thing called hope?

Whatever it was, the only thing I needed to change my vote on primary day was a push. The push arrived as I drove north on I-79 and heard an NPR report about a new Clinton ad that asked who we would want running the country in circumstances such as 9/11 and Hurricane Katrina. This reminded me of the 11th-hour election tactics used in my home state of Massachusetts: level the charge or innuendo at the last minute so the opposition had no time to respond.

As one Pennsylvania Democratic primary voter, I had heard enough. These tactics had to stop. I would no longer be persuaded by the head nodding and finger waving of self-righteousness. I would no longer buy into the surrogate credibility of Chelsea Clinton because she happened to be a well-spoken young woman who thought her mother would make a great president.

On the other hand, I could support a candidate for president who seemed to maintain an even keel in the face of constant attack, and was strong enough to resist appeals to every vote-getting emotion.

Mr. Obama had explained why he did not feel compelled to wear an American flag pin on his lapel. He had refused to renounce his pastor for expressing what many consider to be legitimate black anger at the way our country is run -- until the reverend went too far and forced Mr. Obama to denounce him. And how many candidates for any office have the distinction of simultaneously being misidentified as a Muslim and blasted for contributing $26,000 to the United Church of Christ?

It was becoming clear that this black man who is both black and white was being defined in ways that he was not. Some of this mischaracterization could be attributed to Sen. and President Clinton. Some of it could be attributed to widespread racial attitudes. Some of it could be attributed to Internet rumors and the media.Few if any of these murmurings had to do with Mr. Obama's qualifications to be president of the United States. While I had wanted to be convinced when Mrs. Clinton told us that we should vote for her because "you know what you will be getting," I had to wonder if that included the scare tactics of her advertisements.

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On primary day, I drove to my polling place and voted for Barack Obama and five delegates pledged to him. Though I could not have put it in words at the time, I was voting for hope and against attack, for calm and dignity in the presidency rather than squabbles and scandals, and for the more civil of two styles of campaigning and of being.

I might lose out on my health-care issue, but I might have more reason to respect the leadership of my country.