Sen. Ted Cruz speaks with his wife, Heidi, by his side during a primary night campaign event in Indianapolis. Cruz ended his presidential campaign, eliminating the biggest impediment to Donald Trump’s march to the Republican nomination.

May 3, 2016 Sen. Ted Cruz speaks with his wife, Heidi, by his side during a primary night campaign event in Indianapolis. Cruz ended his presidential campaign, eliminating the biggest impediment to Donald Trump’s march to the Republican nomination. Darron Cummings/AP

Ted Cruz fired his communications director, Rick Tyler, for smearing rival Marco Rubio with the false allegation that Rubio had disparaged the Bible. And Tyler’s transgression is indeed inexcusable: He forgot that his boss prefers to do the smearing himself.

There is something amusing in watching Rubio and Donald Trump come to the shocking discovery that Cruz is a scoundrel.

“Biggest liar in politics!” Trump tweeted Monday. Accusing Cruz of “fraud” and “dirty tricks,” Trump offered a diagnosis: “This guy is sick.”

Rubio, too, detected “a very disturbing pattern of deceptive campaigns and flat-out just lying to voters.”

Where have these guys been?

Just a few months ago, Trump was calling Cruz “a friend of mine and a good guy.” But Cruz has been smearing and fabricating since he arrived in Washington three years ago. As early as April 2013, I observed a perplexing tendency at the Capitol: “Republicans are willing to look the other way when Cruz assaults the facts.” One of his first acts as a senator was to spread the slander that Chuck Hagel, the incoming defense secretary, may have been on the payroll of the North Koreans.

Now that Cruz is concentrating more of his neo-McCarthyism on Republicans, his fellow conservatives have suddenly awakened to the notion that “Trusted” Ted, as his campaign logo would have it, is actually Tricky Ted. And they are — at long last — calling him what he is.

“They just scream, ‘liar, liar, liar,’ ” Cruz complained Monday night to Fox News’s Bill O’Reilly, saying this is because Trump and Rubio “will not defend their record.”

Or maybe it’s because Cruz is lying.

There are signs that the charge is starting to stick. A few weeks ago, when Ben Carson demanded that Cruz fire somebody for spreading the false rumor that he was quitting the race, Cruz declared that he doesn’t “make a habit” of doing such things. But this time he did — even though Cruz firing a staffer for being underhanded is like President Obama firing a staffer for having big ears.

Don’t cry for Cruz, though. Even before the latest flap, the primary map made it almost impossible for him to win the nomination. But he still has the ability to cause havoc in the two-man race between Trump and Rubio. He is, in other words, exactly where he likes to be.

My Post colleagues David A. Fahrenthold and Katie Zezima, writing last week about the 2013 government shutdown that Cruz orchestrated, reported that many Republicans suspect Cruz “always knew his plan would fail but went ahead with it anyway — expecting that he would personally benefit from the exposure, even if his party lost a damaging fight.” His current bid for the nomination is much the same: doomed but damaging.

Republican presidential candidate Ted Cruz (R-Tex.) said he asked campaign spokesman Rick Tyler to resign after he posted a tweet about rival Marco Rubio (R-Fla.) (Reuters)

Republicans could have seen Tricky Ted coming, if they had observed the early signs. In early 2013, he helped torpedo a compromise on background checks for gun owners negotiated by Sen. Pat Toomey (R-Pa.) — not on the merits but with the false allegation that it would lead to a national gun registry. He would go on to allege, among many other things, that the IRS handed over “confidential taxpayer records” to an Obama political operative, and that Obama supported the release of the Lockerbie bomber.

During his campaign for the Republican nomination, his stump speech has become a long string of untruths. In a single speech in New Hampshire this month, he misrepresented numerous things said by Trump, Rubio and Obama, but also half a dozen other public figures. When I found nothing to substantiate Cruz’s claims, I asked Tyler, the now-fired staffer, for supporting material. “Is it incumbent upon our campaign to do your basic research?” he replied.

Then, in South Carolina, Cruz’s campaign was caught using a (badly) doctored image showing Rubio in a jubilant handshake with Obama and the words “The Rubio-Obama Trade Pact.” Coming at a time when pro-Cruz groups were doing shady “robocalls” against Trump and Rubio, and following the Iowa campaign in which Cruz sent out bogus “voting violation” letters, Cruz was not in good shape to weather the Tyler episode. The staffer posted a link to a college newspaper’s false account of Rubio saying the Bible doesn’t have “many answers.”

Back in the 1950s, Joe McCarthy rose during the Truman years with his smears about communists in the government. But when he began to go after fellow Republicans in the Eisenhower administration in 1953, he quickly lost support and within two years was censured by the Senate. Now that Republicans are suffering from Tricky Ted’s smears, perhaps they will come to a similar conclusion about the damage he does.

Twitter: @Milbank

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