Cokie Roberts, left, moderated a conversation in January on why the presidential candidates need to get ready to govern, with, from left, former White House chiefs of staff Joshua Bolten and Thomas “Mack” McLarty and Partnership for Public Service chief executive Max Stier.

If you’re already a Donald Trump hater, you might have heard Cokie Roberts explain on NPR’s “Morning Edition” on Monday why she recently penned a newspaper column in which she took a strong position against the Republican presidential front-runner.

If you’re a Trump supporter, you probably weren’t listening. You probably didn’t read Roberts’s column, either, and you probably don’t care what she thinks.

Trump sure doesn’t.

So if Roberts’s opinion is not going to change the minds of Trump backers, why bother expressing it? For that matter, why have Glenn Beck, Bill Kristol, Arianna Huffington, S.E. Cupp and so many other media figures also come out strongly against the billionaire candidate? Do any of them think that their views will actually change the minds of any actual or would-be Trump backers?

They surely hope so — at least a little. But there’s also a selfish reason for publicly denouncing Trump: They want clear consciences. They want to be able, should Trump actually win the White House, to look themselves in the mirror and know that at least they took a stand.

National Review editor Rich Lowry hinted at this motivation in January, when I asked what he hoped to accomplish through his magazine’s “Against Trump” issue, which featured a sharply worded editorial and 22 essays by prominent conservatives.

“The most important thing is putting a marker down and saying, ‘He’s not one of us. He’s not a conservative, and he’s not what conservatism is,’” Lowry told me. “Just making that point is important, but obviously we want to persuade people.”

Lowry said he knew, even then, that “there are a lot of Trump voters who aren’t going to be persuadable.” He hoped that the National Review’s message might influence some “at the margins,” but the chief objective was simply to put the publication’s position on the record.

Outside the media world, we heard something similar from former Republican candidate Mitt Romney recently, when he explained why he felt compelled to come off the sidelines and deliver a scathing, anti-Trump speech this month at the University of Utah. He told NBC’s “Today” show that “you get to the point where you say — your grandkids are going to say to you, ‘Papa, what did you do to stop Donald Trump?’ I had to finally get out and speak.”

Notice that Romney didn’t say that he spoke out because he believed his voice would snap GOP voters out of their Trumpy hypnosis. He spoke out to avoid the guilt he would feel if he ever had to tell his grandchildren he did nothing.

Roberts wasn’t so explicit in a conversation with “Morning Edition” host David Greene, but a similar sentiment peeked through.

Greene: Objectivity is so fundamental to what we do. Can you blame people like me for being a little disappointed to hear you come out and take a personal position on something like this in a campaign?

Roberts: Yes, I can blame you for being a little disappointed because I think [commentary] is a different role. If I were doing it in your role, you should be disappointed or if I were doing it covering Capitol Hill every day. I can't imagine doing that. But the truth is it is a different role. And there are times in our history when you might be disappointed if I didn't take a position like that.

What Roberts is also saying, I think, is that there are times in history when she would be disappointed — in herself — if she didn’t take a position. She doesn’t want to look back on this campaign and say she was neutral on a candidate whom she believes would deal “a devastating blow” (as articulated in the column) to the United States’ reputation around the world.

There’s nothing wrong with the decisions of Roberts, Lowry or any of the rest to speak up, as their job descriptions allow. But let’s be clear: Their declarations are not all about trying to sway voters; they’re also about trying to sleep at night — and being right when all is said and done.