Religious conservatives are among the most reliable Republican voters. And while most evangelicals voted for Donald Trump in 2016, many of them have been queasy about him ever since. Mormons, too, voted for him in underwhelming numbers. Indeed, as the journalist Tim Carney notes in his new book Alienated America, Trump did best with the GOP primary voters who attended church the least.

So why is it that religious conservatives who voted so reluctantly for Trump — if they voted for him at all — now seem primed to do so in even greater numbers in 2020? Because for many of them, the alternative appears to be voting for late-term abortion and their own cultural marginalization.

I write this as the Senate failed to advance the Born-Alive Abortion Survivors Protection Act, a bill mandating medical care for viable fetuses — supporters prefer "babies" — who survive abortions. Just three Democrats voted for it. All six Democratic senators currently running for president voted no.

The legislation was inspired by moves in Virginia and New York to liberalize laws concerning late-term abortions. Virginia Gov. Ralph Northam (D), who later became controversial for other reasons, defended the bill in his state as allowing what sounded to many ears awfully close to infanticide: "The infant would be delivered. The infant would be kept comfortable. The infant would be resuscitated if that's what the mother and the family desired, and then a discussion would ensue between the physicians and the mother." (Northam's spokesperson later denied this interpretation of his remarks.)

Abortion is a huge issue — perhaps the most important voting issue — for many religious conservatives. It played a decisive role in moving evangelicals and conservative Catholics from the Democratic Party to the GOP in the 1970s and '80s, and the Democratic Party's continued leftward movement on this issue could keep them in the fold.

"Democratic leaders are overplaying their hand and exposing the harsh reality of their platform," argues National Review's Alexandra DeSanctis. "Their promotion of abortion rights after viability doesn't line up with widely accepted medical evidence or public opinion."

As social issues like abortion and gay rights have become cultural flashpoints, Democrats have at times even questioned the fitness for office of people who hold conservative religious views on these subjects. Democratic Sens. Mazie Hirono of Hawaii and Kamala Harris of California, the latter a presidential candidate, objected to a federal judicial nominee's membership in the Knights of Columbus, a previously uncontroversial Catholic social organization.

Another California Democrat, Sen. Dianne Feinstein, pressed a different court nominee about her religious convictions on these questions: "The dogma lives loudly within you, and that's a concern," she said. Democrats also stand accused of adopting a more crimped view of religious liberty for evangelicals, Catholics, and other traditionalists than they did for the religious minorities who were the intended beneficiaries of the bipartisan Religious Freedom Restoration Act, signed into law by President Bill Clinton.

Voting for a thrice-married, twice divorced man known for extramarital affairs, cavorting with Playboy models, vulgar talk, and an itchy Twitter trigger finger — to say nothing of the accusations of racism and sexual harassment or worse against Trump — certainly opens socially conservative Christians up to charges of hypocrisy. It also arguably makes it harder to reach other Americans, including young people, with their religious missions, or work with fellow Christians in communities of color.

But these consequences pale in comparison to voting for a party that stands opposed to the issues nearest to conservative Christians' hearts. As conservative Christian commentator Erick Erickson put it, the Democratic Party "offers me no home and is deeply hostile to people of faith. The president has shown himself to not share my faith convictions any more than the other side, but the president has shown he is willing to defend my faith convictions and is supportive of them."

Erickson didn't vote for Trump in 2016, but announced earlier this month that he plans to do so in 2020. Republican Utah Sen. Mike Lee was one of the most steadfast "Never Trump" social conservatives. He too has said he will endorse Trump in 2020.

Trump has turned out to be at least as good at delivering policy results for social conservatives as a more conventional Republican president, if not better. He may have even shifted the Supreme Court to the right for a generation.

The president's fidelity to his campaign promises with regards to social issues, if not always his marital vows, will likely keep many conservative Catholics and evangelicals in the Republican column come 2020. Their alliance with Trump is not without costs, in this world — the late-term abortion laws themselves appear to be a blue-state reaction to the president's transformation of the courts — and possibly the next. But a look at the Democrats makes it seem to most of these conservatives a price well worth paying.