Are the Evangelical Christians

No! They are a type of strange double standard group. They believe in their own strange prophets. Look at the comments coming from The Republican Roy Moore, who lost to Democrat Doug Jones in a Dec. 12, 2017, runoff to replace Attorney General Jeff Sessions. The exact opposite of Jesus teachings. Christians their NOT

Jeff Sessions, a Methodist who has long enjoyed the political support of white Evangelicals, Scott Pruitt, and VP Mike Pence are Evangelicals

Are there more Evangelicals serving in the 3 branches of Government, that I can't answer. if FBI agents are singled out as bios because they are affiliated with a political party, why doesn't that also apply to a Religious group

Let's start with Ronald Reagan. Before you cry foul, yes, I know Reagan won one of the biggest landslide victories in presidential history and I know that he is an icon in the party. I, too, admired his abilities as a communicator. The man had a gift and a simple charm. However, it was Mr. Reagan who embraced the evangelical wing of the party and put the lunatics in charge of the asylum. - the man known as "Mr. Conservative" - warned against embracing them years earlier, but Reagan did it anyway.

“Mark my word, if and when these preachers get control of the [Republican] party, and they’re sure trying to do so, it’s going to be a terrible damn problem. Frankly, these people frighten me. Politics and governing demand compromise. But these non-Christians believe they are acting in the name of God, so they can’t and won’t compromise. I know, I’ve tried to deal with them.”

The GOP went wrong when they became the party of God. (Thus becoming the American Hezbollah.) No compromise. Stand on principle. Claim to have God's blessings. Attack your opponents as doing evil. It started when the evangelicals took over and it's only gotten worse.

Add in a 24-hour-a-day outrage-generating machine like FOX News, and you have the recipe for the rise of Trump. FOX News was created to keep the base angry - and they're good at that. Angry people get out to vote. However, FOX created a voting bloc monster that they can no longer control. This bloc put Trump in the White House.

In the days of Eisenhower, the GOP was a party of sanity and balance, aside from a few very bad ideas (Wetback, intervening in Iran). Every president makes bad decisions, but lately, the entire GOP is like a laundry list of everything that is wrong with the United States. That's my opinion, anyway.
[R] Senator Barry Goldwater

20/20 Interview with Barry Goldwater (July 1993)
https://www.youtube.com/embed/eu9v7NO_LgU?rel=0