Deputy editorial page editor

A mere allegation. If true.

White House press secretary Sarah Huckabee Sanders, she who has encountered no argument too weak to embrace, had this to say about allegations that Republican Senate candidate Roy Moore molested a 14-year-old girl: "Like most Americans, the president believes we cannot allow a mere allegation, in this case one from many years ago, to destroy a person's life. However, the president also believes that if these allegations are true, Judge Moore will do the right thing and step aside."

So many things to unpack in these 46 words. Let's start with the elephant in the quote, the uncomfortable fact that President Trump was himself the target of such years-old "mere" allegations, more than a dozen, from women who claimed he sexually assaulted them. These were, as then-candidate Trump assured us — and as Sanders, ever willing, reasserted just last month — all "horrible liars," who would be duly sued after the election. Still waiting, Mr. President.

Trump's conveniently flexible standard on accusations — and he is not alone — boils down to: If the accuser points a finger at a Democrat — Bill Clinton, Harvey Weinstein — her word is to be trusted, automatically. If she complains about a Republican, Trump's otherwise dormant devotion to due process kicks in. How can claims from "many years ago" be allowed to "destroy a person's life"?

Some answers: Because they are entirely credible. Because the girl, now a woman, has no conceivable ax to grind — she is a longtime Republican, a Trump voter even — and nothing to gain from coming forward. Because three other women related similar, although less disturbing stories, underscoring Moore's interest in younger girls.

Because the presumption of innocence, while essential in the legal realm, does not mean the elimination of common sense outside it. (Thank you, Mitt Romney, for saying that.) The willing suspension of disbelief has its limits, or should.

Unless, that is, you are a politician dealing with a story you wish would go away. Then you turn instinctively to if-then-ism. "If these allegations are true . . ." said Senate Majority Leader Mitch McConnell (R-Ky.), leading — or not — his prove-it caucus. Disappointingly, among them were women senators who ought to know better. "If it's true . . ." said Alaska's Lisa Murkowski. "If the allegations . . ." said West Virginia's Shelley Moore Capito. "If there is any truth at all to these horrific allegations . . ." said Maine's Susan Collins. Seriously, have you read this article? How can you think about serving alongside this man?

The correct response came from Sen. John McCain (R-Ariz.), who — without hedging — termed the allegations "deeply disturbing and disqualifying" and called on Moore to withdraw.

If-then-ism is the rhetorical cousin of what-about-ism, a bid to deflect attention by questioning whether those complaining about "x" were equally inflamed by "y," when "y" involved someone on their side. If-then-ism represents a similar effort to avoid casting a politically inconvenient judgment.

It is better, sure, than the jaw-dropping alternative: so-what-ism, remarkably flagrant among Alabamians in response to the Moore report. "Much ado about nothing," State Auditor Jim Zeigler told the Washington Examiner. Joseph did it with Mary, he observed. Except, um, minor theological point here — did he?

Still, there is something clarifying in the brutal honesty of so-what-ism. A 32-year-old Moore could put a 14-year-old girl's hand on his erect penis and touch her over her bra and underpants. Trump could shoot someone in the middle of Fifth Avenue. It would not deter their supporters. Okay, at least we know where you're coming from. Your moral parameters are clear in their absence.

If-then-ism, by contrast, is pure cowardly dodge. There are some situations where the fact pattern may be too murky to pass judgment. Not here. What more information do the if-then-ers want? What would be the forum for this factual discovery to take place?

One last strategy — blame the messenger — has come into play here, deployed by Moore and supporters such as former Trump adviser Stephen K. Bannon. "The Bezos Amazon Washington Post that dropped that dime on Donald Trump is the same Bezos Amazon Washington Post that dropped the dime this afternoon on Judge Roy Moore," Bannon said, referring to Post owner and Amazon chief executive Jeffrey P. Bezos and the "Access Hollywood" tape. "Now is that a coincidence?"

No, it's not. Good reporting breeds good reporting. My newsroom colleagues did an incredible job with those stories, as they did in helping break the Monica Lewinsky story two decades ago.

Blaming the messenger is always easier than hearing an unwelcome message. It does not make that message any less true.

Read more from Ruth Marcus's archive, follow her on Twitter or subscribe to her updates on Facebook.