A year ago today, my brother Seth spoke at a naturalization ceremony in Delaware, and made these remarks to a group of new Americans who had just taken the oath of citizenship. He called it one of the most moving occasions he’s ever been a part of.

Tonight, my wife and I watched Alexandra Pelosi’s new documentary “Citizen USA” on HBO. In it, she traveled to all 50 states to witness thousands of immigrants officially become American citizens and explain why they did it.

The majority of them celebrate this as a momentous occasion in their lives, although they have differing reasons for wanting to be an American. The most moving are the women from places like Iran, where they had few of the freedoms they have found here, and marvel at the opportunities afforded them in this nation. Others own businesses, homes, and cars they could never have in their native lands, while some of them talk about the educational opportunities they have taken advantage of in the US. There’s also mention of some aspects of freedom that Americans take for granted — from running water and electricity to walking down the street and kissing your loved one in public, regardless of your sexual orientation, without being arrested.

While some of the ceremonies include portions so corny they could only be American, you can see the life-changing joy in the eyes of these immigrants once they have repeated their oath and been told that they are officially US citizens. During the hour-long documentary, I wondered if my grandparents felt the same way when they came through Ellis Island from Eastern Europe over a century ago.

Here’s the trailer for “Citizen USA,” which will air many times this week on the multiple channels of HBO…