Over the past few months, I've been obsessed with a particular thought - what does it mean to be an American? For many of you, the question may seem silly, even preposterous. But for me, and many like me, it's not a question that's so easily answered.

I have only lived in the US for the last ten years. Before that I lived in Canada, where I was born. Ten years ago if you had told me that one day I would eventually leave Canada, move to the US, raise a family, and work for a great news organization like the Monitor, I would have said you were a bit off your nut. But then I won a Nieman Fellowship to study at Harvard for a year, where I met this interesting woman from Georgia, and the rest is, well, my history.

My wife and I married in 1994, and I received final approval for my green card on Patriots' Day, 1995. For two years, I thought that green card would be all I needed. Most Canadians who move to the US, like my friend David Francis at the Monitor, or former PBS Newshour co-host Robert MacNeil, tend to keep their Canadian citizenship, regardless of how long they live in the US. (I could tell you why, but that is an entirely different kind of essay.) Then one night, as I watched a TV news report about a group of immigrants being sworn in as US citizens, the interviewer asked one woman, a Canadian it turned out, why she did it. "I can't live somewhere and not be able to vote," she said.

She's right, I said to myself. And so I set about to become an American. I studied the Constitution, learned historical dates, studied the necessary laws, and applied for citizenship. Many of my Canadian friends and family members thought I was making a mistake, even if it technically I kept my Canadian citizenship. They could not understand why I wanted to become a Yank.

But I did, along with 1000 other immigrants in a ceremony in a very hot, overcrowded auditorium in Lowell, Mass. three years ago. Which meant the first election I ever voted in was that very interesting one back in 2000. I registered to vote (something we don't do in Canada) as an independent.

The first two years were quite comfortable, and to be honest, not all that different from being a Canadian. But all that changed on September 11th.

Suddenly I was overwhelmed with messages about what it meant to be an American, and not all of the messages were ones that I felt comfortable with. I had never been a flag waver or a nationalist at heart, so the intense pressure from groups like the mainstream media, or even unintentionally from the people on the street where I live, to become both of these was hard to integrate.

When I lived in Canada, it was easy to watch these sort of things from afar and dismiss them offhand with a "Well, what did you expect from the US?" But now I am an American, and it's not so easy to dismiss. Now I find myself in the center of the storm, and I'm not so sure which way to turn.

The one thing I have learned during my time here is that the myth about America being a melting pot it just that, a myth. It's much more of a mosaic glued together with a set of amazing ideas. Unlike any other country that has come into existence in recorded history, America is based on ideas. Ideas constructed around solid cores but with fluid exteriors. It's the secret of its success, IMHO.

It's the interpretation of those ideas that have created, and will continue to create, our greatest struggles. And that is where I find myself now. Struggling with how to interpret those ideas about being an American. And for me, there is only one way to deal with any problem. And that is to write about it.

So this blog, for as along as it is in existence, will be about what it means to be an American. I welcome comments, suggestions, ideas, complaints, observations. I'm certainly going to make lots of my own. And maybe somewhere down the line, when someone asks what does it mean to be an American, I will be able to answer as naturally, in my own way, as all of you who are native-born Americans.

My American Life is written by Tom Regan.