President Barack Obama's inaugural speech was short, grim and eloquent, but one short passage gave me a jolt:

For we know that our patchwork heritage is a strength, not a weakness. We are a nation of Christians and Muslims, Jews and Hindus and non-believers. We are shaped by every language and culture, drawn from every end of this Earth; and because we have tasted the bitter swill of civil war and segregation, and emerged from that dark chapter stronger and more united, we cannot help but believe that the old hatreds shall someday pass; that the lines of tribe shall soon dissolve; that as the world grows smaller, our common humanity shall reveal itself; and that America must play its role in ushering in a new era of peace.

There is a good deal of truth in that, but the stunning thing was Obama's hat tip to "nonbelievers." I have never heard major political speech that acknowledged us; indeed, over the last couple of decades, speeches have generally turned more and more toward God. The common American appeal usually runs in favor of religious diversity, with the underlying assumption that we "all believe in God," we just differ on the details. For the first time, in an address prefaced by a sermon from pastor Rick Warren, no less, we "unbelievers," clunky and negative as that term is, were given our due.

With that, Obama rhetorically enfranchised a large percentage of the population. If you define "unbelievers" as only atheists, agnostics, secular humanists, nature worshippers, and those who describe themselves simply as "non religious," we make up roughly 12-15 percent of the U.S. population. That's a group as big as African Americans.

Atheism itself continues to be unpopular in the political mainstream. There is only one avowed "unbeliever" in Congress and Americans say they would not elect an atheist president.

Obama's acknowledgment is a far cry from George H.W Bush's infamous statement in 1987 that he doubted if "atheists should be considered citizens nor should they be considered patriots." The new president is not only inviting religious minorities inside the tent, he's saying they are an essential part of America's strength.