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

Dan Janison has been a columnist at Newsday since 2007.

Glimpsing Rudy Giuliani’s name among the scheduled speakers for this week’s GOP convention, you recall how the presidential race eight years ago was going to position two New Yorkers against each other.

But the contest between the ex-mayor and then-Sen. Hillary Clinton never happened. Both led early in their respective parties, but failed to make it.

Half that coulda-been contest is about to finally materialize when Clinton is nominated next week. But the Republicans, instead of picking the Democrat-turned-Republican Giuliani who ran City Hall, are nominating a Democrat-turned-Republican from New York who ran casinos and appeared on “The Apprentice.”

So once again, Giuliani serves as a warmup act — not unlike a reliable veteran celebrity making an appearance on the Jerry Lewis telethon or the “Joe Franklin Show,” where the host reminds younger viewers who the guest was.

And with Donald Trump’s family and celebrity friends due to grace the stage in Cleveland, this purportedly political event is likely to feel more like a 21st-century showbiz telethon.

Giuliani’s recent criticism of Black Lives Matter, in the friendly confines of the Fox News Channel, served to put him back in the news cycle. This is nothing new; the two-term mayor has done this same surrogate duty for GOP candidates at other national conventions.

advertisement | advertise on newsday

But the context is unusual. Giuliani, now 72, will be called on to praise a party candidate who condemns in the nastiest of terms the three men who preceded him as nominee — all of whom the ex-mayor lavished praise upon.

In 2004, the ex-mayor stood before Republicans convened in Madison Square Garden and told of the day of the World Trade Center attacks.

“Without really thinking, based on just emotion, spontaneous, I grabbed the arm of then-Police Commissioner Bernard Kerik, and I said to him, ‘Bernie, thank God George Bush is our president’ . . . He has earned a place in history as a great American president.”

But Trump said just a few months ago of the Bush administration: “They lied. . . . They said there were weapons of mass destruction and there were none. And they knew there were none.” Trump turned to Jeb Bush at a debate and said: “The World Trade Center came down during your brother’s reign.”

In 2008, Giuliani said on the rostrum: “Even his adversaries acknowledge — Democrats, Republicans, everyone — that John McCain is a true American hero.”

Not Trump, who trashed McCain’s service, saying dismissively: “He is a war hero because he was captured.”

In 2012, Giuliani sang the praises of Mitt Romney in an ABC News interview at the convention as an “enormously successful” businessman and governor of Massachusetts who would bring competence to the job.

Trump has called Romney a “dope” and “one of the dumbest and worst candidates in the history of Republican politics.”

advertisement | advertise on newsday

The good news for Giuliani, Trump and the party may be that most convention speeches are forgotten anyway before the balloons come down.