Interesting four-screen Politico story on Marco Rubio's faith journey. I was aware that he takes in both an evangelical church and a Catholic one, getting stronger Bible teaching in the first and the classic sacraments from the one The Church left.
I can relate to that. I recall a stretch in grad school where I was taking in Sunday School at a Baptist church and the service at the Assembly of God church next door. That only lasted a few weeks until the AoG preaching headed off into Word-of-Faith land, but for years after that, I would joke that my theology was somewhere in the parking lots between the two.
Later on in 2001, I had a stretch where I was doing a Baptist Sunday school and a Vineyard service before setting up show at the Vineyard.
Rubio seems to be a Bapticostal Catholic, as his evangelical church is Southern Baptist but described as "charismatic" by the Politico piece.
Over the years, I've seen a number of Catholic bloggers with an evangelical-style "personal relationship with Jesus". Those are folks that you don't see if you're solely living in a evangelical universe; the former Catholics making their way into evangelical churches often had a rather nominal faith that went through the motions at Mass but didn't have a heart-knowledge of God. A lack of emphasis in discipleship and liberal takes on theology often help push folks out the door, since their old Catholic church might be rather spiritual dead.
That gives folks who don't know many, if any, faithful Catholics a unkind view of spiritual life. Tack on to that the theological differences and cultural differences between the two and you get some evangelical uneasiness with Catholics, at least theologically.
Those don't always translate into politics. We have seen a number of Catholics do well with evangelical, to the point that Rick Santorum was the de-facto evangelical candidate last-go round. On most of the moral issues of the day, they're fellow travelers. The differences can come more on economics and foreign policy, where pacifist and communitarian streaks can cut across a more individualistic and militaristic streak in American evangelicals; differences on immigration can also create friction.
However, there is quite a bit of room to maneuver for Catholics on those issues, where you can have hawkish free-marketers along with social-justice pacifists under the same roof, so even if you have Pope Francis talking more like a Democrat on economics and immigration, Catholics in the public square still have quite a bit of room to move.
The complicating factor here is that the race has a number of social conservatives. If things boiled down to a Rubio-Trump race, Rubio might get more evangelical support, but the more conservative Ted Cruz might both appeal to evangelical uncomfortable with both Rubio's establishment streak and his Catholicism.