Faith is a critical pillar in the religious ideology of Christian Nationalists. Faith here is not simply a religious virtue, but also a political and social necessity. Just as one must have faith in God, one is also expected to have faith in the basic goodness and competence of political leaders who are acting as representatives of the Will of God. Without faith, the political and religious claims of Christian Nationalism crumble into the sea.
For this reason, doubt and skepticism must be treated as basic enemies. This obviously includes being subjected to the critical questioning of a nonbeliever who offers good reasons to doubt the reliability of the claims being made. Such attitudes may be an important reason why atheists and skeptics tend to be so reviled by conservative evangelicals: the very existence of atheists is perceived as a threat because they demonstrate how a person can live and even thrive without faith in any gods.
The denigration of doubt goes further, though, and includes for example efforts to cover up anything which would cause people to doubt religious leaders and institutions. Scandals, crimes, and hypocrisy are swept under the rug "for the sake of the community" and uncomfortable truths are suppressed as much as possible. The flip-side of this is the promotion of falsehoods which are thought to bolster faith.
In the past such falsehoods were called "pious myths" and often involved someone suffering or dying for their faith as a means to encourage others to persevere in the face of great challenges. Today these myths may depict nonbelievers trying to suppress believers or believers winning amazing arguments against skeptics. No one seems to care if the stories are true or not -- they pass the tales along as if they were simply because they make believers feel better about themselves... and worse about skeptics.
The above image was taken, as one might guess, from a World War II poster warning members of the armed forces about women who look "clean" but might be carrying sexually transmitted diseases. I chose this to convey the idea of warning Christians to be careful about whom they date because of the irony: a number of Christians groups encourage members to date outsider for no reason other than to gain new recruits and "save" their souls.