On the recordMarch 4, 2013
I would be the last person to claim that our Nation is perfect, but as a Nation we have a kind of perfection in us because our founding principle is universal. We are all created equal. People come from all over the world to take us up on that promise. It was immigration that drove us down the track to a broader and more perfect vision of ourselves. They became us. And who we are as in 'We the people' changed and expanded to include new Americans.
Source
congress.gov




