Long before I came to the United States, I was fascinated by the American electoral process. I grew up in Pakistan in the 1980s, during the brutally repressive military dictatorship of President Mohammad Zia ul-Haq, when fear crushed hope.

Finding old copies of Time magazine in my school library, I learnt about primaries and presidential debates - something almost unimaginable in Pakistan at the time. I had a favourite board game where the players' mission was to become the American president. I watched snippets of news, of the Bush-Dukakis race in 1988 and the Clinton-Bush-Perot debates four years later, that we got on our only TV channel. I missed a lot of the nuances, but I developed a deep admiration for the idea that a campaign had to present a vision that people cared about. You had to talk about a better future, and there was a strong undercurrent of hope.

I like to think that my 12-year-old son, the first member of our family to be born in the US, has inherited some of his love of American politics from me. We are practising Muslims and, about four years ago, my son wrote to Mr Michael Dukakis, a former governor and Democratic presidential nominee, asking if a Muslim boy could become president. Mr Dukakis invited my son to his office at Northeastern University, and among my son's most prized possessions now are a picture of himself with Mr Dukakis and his audio recording of their conversation about elections.

Encouraged by Mr Dukakis, my son ran for class representative in sixth grade two years ago and won - by a landslide, according to his own exit polls.

Last year, he ran for student council at his Boston-area middle school. He advised other candidates and wore a suit to school on election days. His schoolmates elected him student council secretary. He is on the e-mail list of politicians and presidential campaigns from both parties. He wants to run for federal office one day and dreams of becoming president. He wants the voting age to be lowered to 12 so he can vote in this cycle.

Until last summer, there was an inherent dignity and grace associated with running for the highest office in the country. At least, that is what we told our son and our nine-year-old daughter. We taught them that hatred had no place in our hearts, or on any campaign trail. We told them that hard work, fair policy and fundamental decency were what voters really cared about. But over the past few months of this campaign, as they heard Republican candidates, especially the presumptive Republican nominee, and their supporters attack immigrants, and Muslims in particular, it has become hard to convince our children that these values matter.

My daughter asked: "Why do the candidates hate all Muslims?" We told her that most people do not judge people based on religion, but that is not what we heard from the campaign.

My son, too, has endless questions, of a different sort: Where are the boundaries in political campaigns? Why is it wrong to defame a religious group if it will get you more votes? Doesn't the end - winning - justify the means? Lately, I worry that this election may be pushing him towards pragmatism over the idealism that America represents to me. I do not want a 12-year-old to give up one for the other so early in life.

I would like my children to always believe that they can change the world for the better and to believe that they do not have to compromise their values or ideals because that is what sells. At the same time, we are teaching them to not raise issues of Islamophobia and the presidential election in school for fear they might be bullied. The contradiction is not lost on us.

In early December, we were celebrating our daughter's birthday at her favourite restaurant, near our home. A woman approached our table and told my wife that she was offended by her and by her headscarf. The kids got scared, and we were too surprised to speak. In our 20 years in this country, my wife and I have received only kindness and support from colleagues, neighbours and even strangers.

After the woman left, we told the waitress what had happened, and she was apologetic and kind. She insisted that the birthday cake for my daughter was on the house. Then, as we were walking out, another customer came over, hugged our daughter and slipped $10 into her hand, as a birthday gift. It was reassuring for our children to see that what we had been telling them about America was true, despite what they see on television.

I am still encouraging my son's ambition to become president. My dream for both my children is that they will grow up in a country that judges them only on the strength of their character, the grandness of their ideas, the decency of their values and, ultimately, their actions. I refuse to give this up. That is what America has taught me to do.

NEW YORK TIMES

• Muhammad H. Zaman is a professor of biomedical engineering and international health at Boston University.