via https://friendlyatheist.patheos.com/2020/01/09/this-brilliant-new-ad-highlights-the-hypocrisy-of-trump-loving-evangelicals/

“Biblical morality” can indeed be molded to just about anything, if you proof text it enough. A Christ-centered morality is another thing entirely. The more I think about it, the crazier it is – evangelicals claim the divinity of Christ as foundational to their faith, and yet draw their morality from just about any and every source *except* His example.

In the 1990s some Democrats were antiabortion. Neither party could exclusively claim the high ground on this deepest of moral issues.

A moral issue so deep that that Jesus never mentioned it, it receives no explicit mention in the Ten Commandments, and nor even any explicit mention of it in the Bible at all (let alone explicit prohibition, or explicit equation with murder).
Metaxas’ diatribe is not “The Christian Case for Trump”, it is rather the Evangelical case for Trump, the Two Commandments of his and his fellow travelers’ Evangelical religion being:
1) No abortions.
2) No gays.
(With the implicit permission to ignore anything that darn socialist Jesus had to say about the poor and downtrodden and so forth.)

If slavery was rightly considered wicked …

Not if the Bible is the basis for your morality its not. The Bible has no problems with slavery, and even lays down rules for it, including differentiated treatment of Jewish and non-Jewish slaves, that bears some resemblance to the differentiation in antebellum US of indentured servitude (for Europeans) versus chattel slavery (for non-Europeans).
On this basis, I’d suggest that “Biblical morality” is an oxymoron.

In the 1990s some Democrats were antiabortion. Neither party could exclusively claim the high ground on this deepest of moral issues.

A moral issue so deep that that Jesus never mentioned it, it receives no explicit mention in the Ten Commandments, and nor even any explicit mention of it in the Bible at all (let alone explicit prohibition, or explicit equation with murder).
Metaxas’ diatribe is not “The Christian Case for Trump”, it is rather the Evangelical case for Trump, the Two Commandments of his and his fellow travelers’ Evangelical religion being:
1) No abortions.
2) No gays.
(With the implicit permission to ignore anything that darn socialist Jesus had to say about the poor and downtrodden and so forth.)

If slavery was rightly considered wicked …

Not if the Bible is the basis for your morality its not. The Bible has no problems with slavery, and even lays down rules for it, including differentiated treatment of Jewish and non-Jewish slaves, that bears some resemblance to the differentiation in antebellum US of indentured servitude (for Europeans) versus chattel slavery (for non-Europeans).
On this basis, I’d suggest that “Biblical morality” is an oxymoron.

To me, this sounds like how you end up with terrible government. If Metaxas’s opinion prevails, then what you have is a sizable portion of the population that essentially says that it’s ok to lie, cheat, steal, abuse your power, be staggeringly ignorant, incompetent, and subvert the democratic process as long as you deliver on a handful of issues and one’s political enemies be painted in a bad enough light.
Which, of course, they always can. One thing demagogues have never run out of is boogiemen and boogie-issues. And then, if people will let them do it, you can be sure some amoral individuals will rise to power and take advantage of that.

Indeed, given that this fight is of “historic importance”, what action can’t he excuse? One imagines if there even is a line.