Are there any unbelievers in Congress ?
I'd say anyone can be a Constitutionalist and enforce those laws first as public duty.
The key is not favoring one's own beliefs above others, but protecting all interests equally under the Constitution.
I find very few people with that faith this can be done, much less conviction and commitment to do it.
So I find most people are biased anyway, and are excluding other groups they oppose or don't know how to deal with to include them.
I wouldn't pick on atheists, I find a lot more humanists who are more open to true universalism who are willing to try this inclusion approach.
so it's not a matter of being theist or nontheist.
It's a matter of respecting equal inclusion and universal language for laws instead of biases that exclude one group while favoring another.
Nobody has that down. We all have to work at it, nontheists and theists, left and right, religious and secular alike.
It takes all types to represent the American public.
I'd put the Constitution first, and then organize representation for all the other groups under that standard.
The issue is whether people take an inclusive approach to conflict resolution (which I find legally necessary to protect all interests equally by law)
or if they are content playing bullying and coercion games that divide and either leave people out or dominate over them to settle a dispute. That political practice of abusing power by majority to dominate by coercion is dangerous and damaging, and I find people in all groups who use this tactic, and people who don't and seek consensus instead, regardless of which affiliation they claim. I call it "restorative justice" to identify the approach that works across political or religious lines; and find this approach even unites atheists and Christians on common values, process and goals, even if their religious views are coming from two totally opposite directions.