Analysis by Chris Cillizza, CNN Editor-at-large

(CNN) -- The speech Monday night by former Ohio Republican Gov. John Kasich is already drawing massive amounts of attention. A dyed-in-the-wool Republican who is turning from President Donald Trump to support former Vice President Joe Biden! Kasich is speaking truth to power!

Except, well, in terms of actual voters who might be persuaded by Kasich's speech, it's likely to not have much of an impact at all.

This whole Republican-speaking-at-a-Democratic convention (and vice versa) isn't a new thing.

In 2004, Georgia Sen. Zell Miller, a Democrat, spoke at the Republican National Convention in support of a second term for President George W. Bush.

In 2008, Joe Lieberman, who had been the Democratic vice presidential nominee eight years prior, delivered a speech at the RNC for his friend John McCain.

In 2016, Michael Bloomberg, elected mayor of New York City as a Republican, spoke at the Democratic National Convention.

Do you remember what was said in any of those speeches? Probably not -- because none of them was terribly memorable.

See, the idea of someone crossing the party aisle to deliver a speech is way more intriguing than the actual address itself. It sounds great for Kasich, a man who ran against Donald Trump in the 2016 presidential primary, to publicly come out for Biden. But the actual speech is very, very likely to be forgotten soon after it's given.

(Side note: Kasich is a CNN contributor.)

Here's why.

Democrats don't need any convincing to vote for Biden. And they certainly aren't likely to take their cues from a Republican governor and presidential candidate.

Many Republicans don't trust Kasich. He's made his opposition to Trump very clear over the years. It's virtually impossible to not know before today that Kasich isn't a fan of Trump. That he is willing to go the Democratic Convention and declare those views won't be perceived as an act of conscience but rather as an act of cowardice by those Republicans. They -- and potentially Trump himself -- will cast Kasich (as well as other Republicans speakers at the DNC like Meg Whitman and Susan Molinari) as not-real-Republicans anyway, merely Republicans in Name Only (RINOs) playing to their friends in the media.

Of course, the Kasich speech isn't aimed at either Democratic or Republican partisans. It's theoretically aimed at persuadable voters who are undecided about who to choose in November. And who, again theoretically, will be swayed by someone like Kasich who has spent his entire life in the Republican Party, but sees supporting Trump as a bridge too far.

Frankly, I'm skeptical that there are enough fence-sitters to make such a speech truly worthwhile. (Trump is the most polarizing president in history.) I'm also less than convinced that Kasich (or any former Republican elected official) would be the voice that would tilt these undecideds toward Biden. Inside Elections editor Nathan Gonzales said it well here:

"I think Democratic Convention planners are overthinking this. Democrats have so many younger and more diverse voices in the party. Any of them would have just as much of chance at persuading GOP voters as this lineup."

Agreed. If past is prologue, Kasich's speech will be a ripple, not an eruption. And ripples tend not to change a lot of minds.