President Donald Trump signs the hat of Bruce Adams, chairman...

President Donald Trump signs the hat of Bruce Adams, chairman of the San Juan County Commission, in Salt Lake City on Monday after signing a proclamation shrinking Bears Ears and Grand Staircase-Escalante national monuments in Utah. Credit: AFP/Getty Images / SAUL LOEB

Alan K. Simpson, the former Republican senator from Wyoming, once observed that, “If you have integrity, nothing else matters. If you don’t have integrity, nothing else matters.”

Simpson was speaking about individuals, of course, but he could just as well have been talking about political parties. Without integrity they are hollow vessels; they speak neither with substance nor moral authority.

The Democratic Party surrendered its moral authority in 1998. That was the year President Bill Clinton’s relationship with a 23-year-old White House intern came to light.

What Clinton did was morally wrong. We shouldn’t need to recount the ways in which that statement is true, even in an era of moral ambiguity.

Democratic Party leaders and prominent American liberals had a choice to make that year: Demand the resignation of their own leader or circle the wagons around him and fight off criticism at any cost.

They chose the latter.

The Republican Party surrendered its moral authority in 2016 when it freely accepted an unprincipled man as its leader. We shouldn’t need to recount the ways in which that’s true either. Donald Trump has proven himself morally reprehensible over a lifetime.

As long as Trump leads the Party of Lincoln — it still hurts to write those words — the Party of Lincoln will be dead to millions, just as the Democratic Party was anathema to so many who watched it prioritize politics over principles in 1998.

There is no getting around it.

The Republican Party is viewed favorably today by just 30 percent of Americans, according to a recent CNN poll. The Democratic Party doesn’t fair much better at 37 percent, both figures representing 25-year lows for the respective parties. The only good news for either is how disgusted Americans are with the other.

For those who work in politics, it’s not that hard to understand how we got here. Party loyalty is considered more valuable in today’s political industry than personal ethics are. Almost anything can be overlooked if it protects the team. And why not? Those working inside the political bubble have come to genuinely believe, in many cases, that their side is ever-virtuous and that the other is ever-villainous. There are no shades of gray; the cause supersedes all.

That may partially explain why some Republicans are still defending AlabamaSenate candidate Roy Moore, who’s been credibly accused of molesting underage girls. Some want the extra Republican vote in the Senate no matter the cost; others just plain hate the other party enough to think nothing of helping an accused child molester get elected.

Thomas Monson, the now 90-year-old president of The Church of Jesus Christ of Latter-day Saints, offers us a nifty quote to stand alongside Simpson’s: “Perhaps the surest test of an individual’s integrity,” he once said, “is his refusal to do or say anything that would damage his self-respect.”

On Monday, Trump gave Moore his full-throated endorsement in Alabama’s Dec. 12 special election, proving that he has neither — just as the Republican Party is doing by willfully embracing him as its leader.

William F. B. O’Reilly is a consultant to Republicans.