Barack Obama does not appear to believe in a strict separation of church an state, which is a shame because opposition to church/state separation is a keystone in the Christian Right's assault on modernity and the Enlightenment. Barack Obama does not come out to openly deny that church and state should be separated, of course, but he liberally uses Christian Right rhetoric, misinformation, and even lies in a way that would tend to undermine confidence in and support for separation.
In his "Call to Renewal" Keynote Address of June 28, 2006, Barack Obama said:
But a sense of proportion should also guide those who police the boundaries between church and state. Not every mention of God in public is a breach to the wall of separation - context matters.
Of course context matters — context always matters in every church/state separation issue. Barack Obama is being disingenuous because no one argues that "every mention of God in public is a breach to the wall of separation." On the other hand, this claim is often used by Christian Nationalists to caricature and then dismiss church/state separation and those active on behalf of separation.
Barack Obama only seems to imagine a narrow context when evaluating church/state issues. He should look at the larger context which includes Christians harassing, intimidating, threatening, and sometimes assaulting minorities who do don't fall in line or who challenge "voluntary" religious observances.
Context matters, and the fact is the overall "context" is an America where Christians have been privileged, have abused their power over others, and have been accustomed to the idea that they and their religion should be treated as superior to all others. In recent years we've had incidents like Jews who were chased out of their homes by Christians who thought they owned the community. In Oklahoma, a community tried to chase an atheist family out of the state — and then tried to get the father convicted under false charges of assault when he stood his ground.
Christians are reacting so violently to challenges to government-endorsed religious rituals because they don't like losing those privileges — it's precisely the same sorts of reactions America saw when whites started to be denied their special race-based privileges. When a group is privileged long enough, members end up seeing their privileges as their rights (or stop seeing the privileges at all) — and when minorities demand equal treatment, they are derided as demanding "special rights."
What if Barack Obama had said "Not every expression of white privilege in public is an infringement of civil rights — context matters." Would he be right? Perhaps — but he wouldn't say it because he recognizes that white privilege is wrong. He doesn't yet recognize that Christian privilege is equally wrong. Every official government mention of "God" is an endorsement and expression of support for a particular conception of a particular god and, therefore, endorsement and support for a particular religious position held by some but not all Americans.
People who happen to share that conception of this god generally don't recognize the fact they are being privileged because their god usually plays an important role in everything they do — it's an unconscious ideology that prevents them from seeing anything amiss with one more expression of their beliefs from a different source. Such privileging of one religion is a problem, though, because it sends the message that adherents are politically privileged. In the long run, this message of privilege becomes a message of superiority, creating a situation in which people are willing to employ violence in defense of their privileges. It's only to be expected because people construct most of their personal and communal identities around those privileges.
Whites have used violence to defend white privilege; heterosexuals have used violence to defend heterosexual privilege; men have used violence to defend male privilege; Christians have used violence to defend Christian privilege. The story is always the same, all that changes is which group is being unjustly privileged. It's the duty of liberal, democratic governments to not only tear down such privileges, but to protect the minorities who might suffer from retaliation.
Why is Barack Obama using the rhetoric of Christian Nationalists? There is no indication that he himself is a Christian Nationalist, but this wouldn't be the only time that he used such rhetoric to disparage secularists and secularism. In a 2007 speech to United Church of Christ's Iowa conference, Barack Obama said:
Doing the Lord's work is a thread that runs through our politics since the very beginning. And it puts the lie to the notion that separation of church and state in America means somehow that faith should have no role in public life.
Once again, no one has actually said that "faith should have no role in public life," but that's a lie which Christian Nationalists love to repeat in order to encourage conservative opposition to church/state separation. Barack Obama here is misleading people in the same way that Christian Nationalists do by playing on multiple definitions of the word "public." There is "public life" in the sense of what people can easily see in public (as opposed to kept hidden in private) and then there is "public life" in the sense of the government.
The separation of church and state does not prevent people from expressing or practicing their faith in public, but it does prevent the integration of their personal religious faith into the government. Presumably Barack Obama knows that people's faith can be expressed and practiced in public, so that only leaves a desire for "faith" to play a role in the government. If Barack Obama is trying to say that his personal religion should be integrated into the government of all citizens — including those who reject his religion — then he is in effect denying that church and state should be separated.