Radio show host Rush Limbaugh speaks at a forum hosted by the Heritage Foundation in Washington, in this June 23, 2006 file photograph. (REUTERS/Micah Walter/Files)

Perhaps the biggest question Marco Rubio's nascent presidential campaign faces is whether conservatives will forgive him for spear-heading comprehensive immigration reform in 2013.

And one very well-known conservative has.

On his radio show Tuesday, Rush Limbaugh devoted plenty of time to praising Rubio in what can only be described as glowing terms. Yes, he said he wasn't happy about the "amnesty" thing, but he also seems to have pretty quickly moved past it. He even volunteered some excuses for Rubio.

A sampling:

... Marco Rubio is a serious man, he has a serious message, and he has a very unmistakable joy in spreading that message, in informing people. He knows how to deliver it.  He knows how to deliver it live.  He doesn't have to announce on Twitter.  He doesn't have to announce with a series of posts on social media.  He can do it live in front of real people with a real camera.  And he's an emotional speaker.  In fact, at some point last night, a couple of points it looked to me like he almost might tear up.

Now, I know Rubio has lost a lot of luster with some people on the Tea Party side because of his flirtation with the Chuck-U Schumer gang on amnesty and immigration.  You can maybe chalk it up to two things.  Chalk it up to novice naivete, trying to get his feet wet and establish himself within the power circles of the Senate.  Or another explanation for it could have been that, given his Hispanic heritage, he almost had to, in the sense of identity politics, if he had any chance at all of securing any votes from that sector, he had to come out in favor of it.  But whatever, he's walked it back now, and we'll just see how this is all gonna play out with Tea Party people.

...

The one thing about Rubio, whether you disagree with him on what he did with amnesty and then walked it back or not, he does not have a likability problem.  He is instantly likable.  He's motivational.  He's inspirational in a Reaganesque way because he has that family story, and he relishes telling that story.  He thinks it's inspirational.  It was to him, and he wants it to be for everybody.

He is a great communicator, significant communicator, has a conservative message.  Just over here he has that misstep on immigration with the Tea Party.  Time will tell if that can be overcome.  Now, we will see also if his policies match his rhetoric.  His rhetoric is great, his persona is great, his energy is great. He's a natural leader, it appears, and there will be a certain number of people who will relish and enjoy making Rubio their champion.  He's not gonna have to ask them, in other words.  He's not gonna have to do what Hillary is doing (imitating Hillary), "I want to go out, I want to be your champion. I want to be your champion, everyday people."

Key word here: Reaganesque.

The Limbaughs of this world, quite simply, don't just forgive something like "amnesty." That Limbaugh is willing to set that aside in this case is a testament to two things:

1) That conservatives want to be able to like Rubio because they see his potential, and

2) That Rubio did himself plenty of good by bringing his immigration message directly to conservative talk radio.

As we wrote at the time, Limbaugh gave Rubio plenty of credit for having the courage to bring his case for immigration reform directly to Limbaugh's airwaves. "You're meeting everybody honestly, forthrightly," Limbaugh said with Rubio on the line in January 2013. "You’re meeting everyone halfway."

[Marco Rubio: The ‘upside’ candidate of 2016]

At the time, I remember being struck by how well Rubio handled himself during these interviews, bringing such a message into hostile territory. And it looks like he did himself plenty of favors with it, no matter that the bill wound up failing.

There will certainly be people who can't forgive him for the immigration thing, but a good messenger can overcome such obstacles. And Rubio, as Limbaugh notes, can be a really talented one.