Dan Janison Melville. N.Y. Tuesday January 26, 2010. Daniel Janison,

Dan Janison has been a reporter at Newsday since 1997.

The daily paradoxes of the Cleveland GOP convention are so plain and plentiful, they register little surprise or notice.

And the elevation of the bombastic Donald Trump, with his rare ability to contradict himself within a 24-hour news cycle, seems to advance what some call the “post-factual” era.

Which brings us to Day 3, on Wednesday, when Sen. Ted Cruz, the second-place finisher for the nomination, is scheduled to speak.

As Cruz steps up, everyone in the arena could be forgiven for recalling the slur “Lyin’ Ted” — courtesy of Trump’s name-calling during the primaries that party professionals will now chalk up to “hard campaigning.”

Texan Cruz proved widely unpopular among Republican voters for a thousand reasons, and was crushed in the primaries, including this state, after Cruz expressed disdain for “New York values.”

But the day of the crucial Indiana primary, the ex-Democratic real estate mogul did something to Cruz that proved amazingly post-factual.

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Trump cited a story from the National Enquirer tabloid that reported — based on a comically grainy photo — that Cruz’s Cuban immigrant father Rafael in 1963 was handing out pro-Castro leaflets alongside Lee Harvey Oswald.

Trump’s cynical words that day: “His father was with Lee Harvey Oswald prior to Oswald’s being — you know, shot. And nobody even brings it up. They don’t even talk about that. That was reported, and nobody talks about it.”

Cruz called the suggestion an outrageous fiction.

Trump the previous month had retweeted a post from one follower comparing their wives, based on appearance.

Now Cruz’s coming appearance could feel to history buffs like Joseph Welch, who served as special counsel for the U.S. Army, appearing before a gathering to nominate his nemesis, the censured smear artist Sen. Joseph McCarthy. (Perhaps coincidentally, Trump had McCarthy’s counsel Roy Cohn as an early mentor.)

At 45, Cruz seems to believe he has a future in the party. He has called Trump, 70, “utterly amoral,” a “pathological liar” and “a narcissist at a level that I don’t think this country has ever seen.” Should Trump lose badly in November, Cruz can be expected to plan a comeback in 2020 and say he never gave up on the GOP. He’s due to return to the Senate.

Cruz is expected to thank his hundreds of delegates. Trump hatchet man Newt Gingrich, a former House speaker who also addresses the convention on Wednesday, has said a Cruz refusal to endorse Trump would mark a “betrayal.”

But we all know that if you don’t like a politician’s opinion, just wait a few minutes — or until the needs arises to suck up to someone new. So it remained a question Tuesday as to whether and how much Cruz might abase himself when he takes the stage.

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Same goes for the man Trump childishly ridiculed as “Little Marco,” aka Sen. Marco Rubio of Florida, who also failed to muster much support against the New Yorker. After on-again, off-again plans, his appearance was on again for Wednesday.

Wisconsin Gov. Scott Walker, an early dropout from the presidential race who’s been critical of Trump, also is due to step up to the stage. Trump has publicly derided him as not doing very well in his current job.

The words of the candidate and those who now bow to him speak for themselves. The question is which ones, if any, are worth believing, and when.