Did you see the headlines last week about the back-and-forth between Pope Francis and Donald Trump?

When asked about Trump’s suggestion of building a wall at the Mexican border, the Pope responded, “A person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian.” Trump responded, “I am a Christian and I am proud of it," and "For a religious leader to question a person’s faith is disgraceful." (Catch the whole story here in USA Today.) 

Politics aside, the exchange between the Pope and Trump raises an interesting question: What Makes a Christian?

The answer may not be as obvious as it first seems.

• Is it being baptized? But what if someone were to reject their baptism? To some, she is still a Christian; others would say not.

• Is it, as some evangelical traditions demand, “Accepting Jesus Christ as your personal Lord and Savior”?

• Is it being a member of a church?

• Following a set of beliefs, like the creed, or political policy positions? Yet most people don’t accept everything in any ancient or modern creed entirely.

• Is about it following Jesus? And what does that look like? How do you tell?

• Is it just self-identifying as a Christian apart from any Christian institutions? Is it a feeling?

• Can one be Christian but also Buddhist? How fluid can religious identity be?

Other religions have similar considerations. Judaism is an ethic identity, so things are a little clearer. However, within Judaism itself, people differ on what makes a Jew. Orthodox and most Conservative traditions say that to be a Jew one must be born of a Jewish mother. Reform and Reconstructist traditions would say that it can pass through the father as well.

As you can see, religious identification can be a tricky thing. And its a timely question as people (maybe you!) don't identify with religious traditions and institutions in the same ways as they once did.