Why POTUS can't go to church

Amy Sullilvan has a post up at Time's Swampland about why present day presidents can't really go to church. Certainly, it is the case that the modern presidency, and the need for security, would be horribly intrusive on other parishioners. It is also the case that any President is likely to find it difficult to pray when everyone is looking at him. The chapel at Camp David seems to be the best option, and it is an option that President Obama exercises most weekends.