Several major conservative leaders, including former Arkansas Gov. Mike Huckabee, South Carolina Gov. Nikki Haley, Wisconsin Gov. Scott Walker, and New Jersey Gov. Chris Christie, have been invited to speak at the 2012 Republican National Convention in Tampa, Fla.

That’s not a bad lineup.

However, as of this writing, three notable figures are still missing from the list of announced speakers. And we’re not talking about right-leaning celebrities or conservative politicians who have recently found themselves in the spotlight; we’re talking about three public figures who, at one time or another, have played a major role in rallying the conservative base.

But before we get ahead of ourselves, let’s get this out of the way: National conventions are little more than an excuse to unite the base and fire up voters. Sure, a few people might show up and dispute their party’s candidate, but, as it has been for quite some time, both parties usually have their nominations tied up long before the conventions roll around.

Therefore, one of the only reasons these rallies still exist is to stoke voter enthusiasm.

That being said, here are three public figures the GOP — if it’s really interested in firing up and uniting the base — should perhaps give a second look:

Newt “Shoot the Moon” Gingrich

Here Are 3 Notable Exclusions From the Republican National Convention

While there are many who dispute Newt Gingrich’s conservative credentials, even arguing that he falls hard on the side of “progressivism,” there’s one point on which most everyone can agree: He’s a gifted orator.

Indeed, during the 2012 Republican presidential primaries, who was it that received multiple standing ovations for his eloquent and impassioned defense of conservative principles? It wasn’t Gov. Rick Perry (R-TX):

However, despite his ability to energize audiences and get people on their feet, there may be a few reasons why the GOP chose to keep Gingrich away from the microphones.

First, there could still be some bad blood between the former Speaker and the presumed Republican presidential candidate Mitt Romney. Second, as TheBlaze’s Meredith Jessup notes, “GOP leaders were probably also wary of giving Gingrich a speaker’s spot after his tepid endorsement of Romney earlier this summer.”

“I don’t particularly dislike him as a person,” Gingrich said during his halfhearted endorsement.

As Jessup points out, this probably isn’t the kind of enthusiasm the GOP is looking for. Still, one can’t help but feel that (given the chance to speak) the former Speaker would bring down the house.

Michele “Queen Bee” Bachmann

Here Are 3 Notable Exclusions From the Republican National Convention

Known to conservatives as the “Queen of the Tea Party” and referred to as the “Queen of Rage” by liberals, Rep. Michele Bachmann’s role as a leader on the right cannot be disputed. Sure, some may disagree with her stances and think her too “extreme,” but, again, if the GOP wants to get voters pumped for November, it should keep in mind Rep. Bachmann was one of the chief architects of the 2010 “Red Wave.” If the GOP wants to see something like that happen again, perhaps having “The Queen” on hand wouldn’t be such a bad idea.

So is there a reason she hasn’t been invited?

“Bachmann, along with four other members of Congress, have requested that [Huma] Abedin’s family ties to the Muslim Brotherhood be formally investigated — a move that has not won her any popularity contests, even among fellow Republicans like John McCain, who subsequently took to the Senate floor to openly chastise the congresswoman over the matter,” TheBlaze’s Tiffany Gabbay reminds us.

Which is to say, it’s entirely possible the GOP chose to exclude Rep. Bachmann so as to avoid having an outside issue such as Abedin’s ties to the Muslin Brotherhood distract from the convention’s focus on the economy.

Still, “distraction” or not, if the GOP’s interested in getting voters “jazzed” about the upcoming election, Rep. Bachmann’s charisma and energy is far more likely to resound with conservatives than say, Jeb Bush or Sen. John McCain (both scheduled to speak at the convention).

Ron “The Doc” Paul

Here Are 3 Notable Exclusions From the Republican National Convention

First off, we’re well aware Sen. Rand Paul is speaking at the convention. Second, having Sen. Paul speak is not exactly the same as having his father who, for more than 30 years, has been an unflinching advocate for serious economic reform. In fact, we’re pretty certain it’s this legacy that has earned Rep. Ron Paul the backing of an entire movement. Indeed, as we have noted before on TheBlaze, it’s no secret that the Texas congressman has something of a corner on the youth vote.

Why does that matter? Consider the following:

[there has been] a noticeable decline in youth support for President Obama’s 2012 re-election campaign. If these reports are accurate, and young voters are indeed abandoning President Obama en masse, then the implications for the 2012 election could be enormous.

Recall that in 1980, President Ronald Reagan was able to win the White House with strong support from voters ages 18-29.

“Reagan brought an entire generation to the Republican Party in 1980, and in 1984 he won the youth vote by 20 percent,” writes Margaret Hoover in the Wall Street Journal. The youth vote, historically pro-Democrat, populated Reagan rallies with cries of “Four more years!” according to PBS’ “Reagan” history series.

In 2008, President Obama won a full 68 percent of the youth vote, the biggest in American presidential history. And this was no small thing. It can easily be argued that youth vote guaranteed him the presidency.

So what does the current state of the U.S. economy [and] a loss of youth support for President Obama’s re-election campaign … mean? It could mean that the youth voting bloc is up for grabs and the entire 2012 election is contingent on whoever wins their support.

As mentioned in the beginning of this article, conventions aren’t just about firing people up — they’re also about uniting the base. There is a large and active voting bloc out there that likes Rep. Paul in a big, big way and it might not have been a bad idea to include him on the list of speakers. Furthermore, if it is indeed the aim of the convention to focus on the economy, who better to speak on the subject than Rep. Paul?

Now it’s entirely possible that Paul didn’t want to speak and it’s entirely possible that the GOP invited his son as some sort of compromise. All we’re trying to say is that there is an active and energetic voting bloc out there and we’re not entirely certain having his son speak at the convention will be enough to win them over come November.

BONUS: Sarah “Mamma Grizzly” Palin

Here Are 3 Notable Exclusions From the Republican National Convention

This is an odd selection (that’s why it’s a “bonus”). Former Alaska Gov. Sarah Palin announced last week that she won’t be speaking at the convention, adding that she’s “excited to hear from this year’s candidates.”

“Sarah Palin not speaking isn’t the news story. … The big question is whether she was invited at all, or if she just declined the invite,” writes TheBlaze’s Mytheos Holt.

Indeed, was she not invited or did she decline? Her announcement tells us very little.

“Palin says in a statement that she supports Mitt Romney and his running mate, Wisconsin Rep. Paul Ryan, and will focus on grassroots efforts to help get the pair elected,” the AP reports. “She says everything she said at the 2008 convention still holds true — including her prediction that President Obama would set out to fundamentally transform the country.”

And it’s still up in the air as to whether she’ll attend the convention at all.

Now, considering the fact that she has become a wildly successful kingmaker, as well as the fact that her, um, less-than-energetic 2008 counterpart was invited to speak in Tampa, we can’t help but wonder: Was she invited or not?

And there you have it. Feel free to sound off in the comments section if you disagree with any of the selections on this list.

Follow Becket Adams (@BecketAdams) on Twitter

All photos courtesy The Associated Press. This story has been updated.