"I’m trying to imagine a Fundamentalist Baptist Pastor being invited to speak to congress"
Queen Elizabeth II - on her state visit to the US in 1991 - was invited to speak to Congress:
A devout Christian, she is.
And head of the state religion, the Church of England.
You wanted to be separate from the rule of a past monarch of my country, King George III, did you not? Otherwise, what was the point of the War of Independence, thus another George - Washington - and his colleagues drawing up the basis of your country, the US Constitution: which mentions verbatim 'God', 'Jesus' and 'Creator' a grand total of... zero times?
...but I guess it's okay when that head of state - as Pope Francis is, of Vatican City - in her case of the UK, with a state religion, is the same as that of George III: Church of England: Protestant.
And she closed with "May God Bless America."
Try to imagine the MC Escher-esque multi-dimensional paradox you're now in. If your one-dimensional mind can handle that kind of denominational mindfuck, 'Doc'.