You can be blinded by the right, but you shouldn’t refuse to see in the cold light of day.

Or, put another way, what does David Brock’s latest book, “Killing the Messenger,” have to do with Tuesday’s Democratic presidential debate at the Wynn Las Vegas? I think the answer is, plenty!

Let me explain. First, who is David Brock? Those of us who remember Bill Clinton’s presidency way back in the 1990s will recall the Arkansas Project and a billionaire named Richard Mellon Scaife. The Arkansas Project, which was funded by right-winger Scaife, was dedicated to one purpose: destroying Bill Clinton’s credibility both while he was running for the White House and after he took up residency.

The hired gun for that dirty work was David Brock. And he was really good at his job.

But in the late 1990s Brock had a moment. He realized the stuff he was virtually making up to sully the president and lower his polling numbers — things such as credibility and trust — were so wrong and so harmful to our democracy that he quit his job and wrote a best-selling book. It was called “Blinded by the Right” and exposed the tactics being employed by the right wing, whose mission it was to diminish Democrats in the public’s eyes without regard for any semblance of truth.

Fast-forward to today. Brock, who started the powerhouse investigative journalism effort called Media Matters (which focuses on the continuing effort of the right wing and its media allies to continue what Scaife started), has written another book.

“Killing the Messenger” was released last month. The release date is important because the subtitle is “The Right-Wing Plot to Derail Hillary and Hijack Your Government.” You will see why in a moment.

The chapter names are telling. Here are a few. “Return to Little Rock,” “The Part of Koch,” “The Romney-ization of Hillary Clinton,” “E-mails: The ‘Times’ Strikes Again,” “Getting Ready for Hillary,” “How to Beat Hillary Clinton,” “How Benghazi became #Benghazi” and “The Haters and Enablers,” to name a few.

I know, I know. These are not right-wing-friendly chapter titles. But it is not the titles that count. It is what is written in the chapters beneath them.

I am mentioning the book for two reasons. First, Brock will be in Las Vegas for a book party Monday evening hosted by Sen. Harry Reid. Second, I believe that what Brock writes about the Benghazi hearings is absolutely spot on and, if that weren’t enough, the incredulous flameout of Speaker of the House-in-waiting Kevin McCarthy confirms what Brock has uncovered.

For example, in the chapter about Benghazi becoming #Benghazi, Brock writes:

“One of Hillary’s goals in ‘Hard Choices’ (her recent book) was to put the Benghazi pseudoscandal to bed. She wrote about the tragedy with candor and insight and emotion. Hillary made clear that as secretary of state, she took responsibility; she took action focused on how to prevent future attacks and she was transparent with the public throughout the ensuing investigations of the attacks. For reasonable readers, that was the end of the story.

“But ‘Hard Choice’s’ passages on Benghazi only inflamed her critics, for they were given nothing new to work with. Thus the right’s shameless, macabre efforts to politicize the deaths of four Americans in the attack on our military compound in Benghazi will persist into the 2016 election and perhaps beyond.”

Brock spends page after page recounting in agonizing detail the events that really did happen according to every investigation into this matter. And then:

“… So why do they persist? The answer is that while conservatives would be thrilled to find some previously undiscovered evidence to blame Hillary Clinton for the Benghazi attack, they don’t need it for their strategy to work. The right, no doubt, has polled the issue, so they know that voters have heard enough about Benghazi to believe that there is blame to be assessed somewhere in the government. They know they’ve succeeded in sowing the suspicion that there is some further truth not yet told.

“They also know that, as long as they continue to talk about Benghazi as some kind of unsolved mystery, the media will continue to hype the ‘ongoing investigation’ into “what really happened that night.”

The chapter ends with Brock writing that what Benghazi did for the right was provide opportunity to hurt Hillary Rodham Clinton’s reputation as a strong secretary of state and suggest to voters that she was nothing more than “a self-serving liar.”

“And it was the foundational element of a media dynamic in which everything the Clintons say or do is scandalized — even their path-breaking global philanthropy.”

Practically every chapter in “Killing the Messenger” has Brock setting up the GOP storyline, then debunking it with facts. Remember, he is the guy the Republicans hired to write the lies in the first place. But, like a reformed smoker, he has become the right’s worst nightmare because he knows the playbook.

I chose the Benghazi chapter for two reasons. First, it is the most blatant effort by the scandal mongers to exercise their right to accuse no matter how wrong they may be. An unsuspecting electorate, eager to blame someone for what happened that night, has been all too willing to accept the premise that it was all Hillary’s fault, regardless of what the facts say.

When you see polling that suggests Hillary is untrustworthy, it proves the plan is working. Truth has no bearing on the right’s actions. Polling numbers justify everything the right does. And, it would have gotten away with it had not last week happened.

It is too easy to dismiss what Brock writes because far more people won’t read his book than will read it, and a 24/7 assault on his words will drown out whatever common sense his facts might otherwise engender.

But here’s the rub. This next presidential election is far too important to this country to allow a strategy of misinformation to confuse the electorate to the point that it might not support someone who, arguably, is the single best candidate for president in a generation.

That is why last week is so important. Last week the once and no longer future successor to the speakership of the U.S. House of Representatives, Kevin McCarthy, told the truth.

In an interview in the relative safety of Fox News, McCarthy bragged: “Everybody thought Hillary Clinton was unbeatable, right, but we put together a Benghazi special committee. ... What are her numbers today?”

I am sure he didn’t mean to say that much, because he not only cost himself the coveted title of Mr. Speaker, he admitted what David Brock was writing — that all those committee hearings were nothing more than an effort to use taxpayer money and taxpayer institutions to pursue a political strategy of destroying the candidacy of a qualified American seeking the highest office in the land.

For the Republicans, what McCarthy did was expose their nefarious and un-American activities and more than likely effectively end their cynical strategy of using Congress to adversely affect Hillary Clinton’s presidential aspirations.

So McCarthy’s colleagues punished him. He gave up their secrets and they threw him to the curb. What they do next is anybody’s guess.

But, what the American voters should do is more predictable. Facts do matter. Opinions can vary, but facts are facts. Just because you heard it on some “news” channel does not make it so.

If you want to be responsible, read Brock’s book. Believe me, he knows what he is talking about. Remember, he is the guy who used to make this stuff up when his job was to destroy the Clintons. He was once blinded by the right.

The rest of us don’t have that excuse. It is our own fault if we plain old refuse to see.

Brian Greenspun is owner, publisher and editor of the Sun.