(CNN) In the grand, all-encompassing, transfixing behemoth of a story that is the Russia investigation, there is one simple question that floats off the tongue every week or so: Why hasn't President Donald Trump fired Rudy Giuliani?

You may ask: After Rudy's recent on-air gaffes, should we expect him gone -- or relegated to a less visible role? Trump has real lawyers, so why does he need a TV lawyer? More to the point, does Giuliani even know what he's talking about? Or, why keep a lawyer whose changing answers and explanations may create more legal problems for the president?

All legit questions, for which there are no foolproof answers. But let's try.

First, Giuliani really is the TV lawyer -- the presidential mouthpiece unafraid to defend, even when it takes him -- and sometimes his client -- into murky territory. He takes no direction from the real lawyers before his appearances, multiple sources say. They would rather deep-six the interviews, but then await -- and often receive them -- with dread.

Giuliani does, however, talk to Trump -- which makes his public utterances even more high-wire. For whom does he speak? Where did he get his information? From the lawyers or the President, or both? Does he even have any real mastery of the facts of the case? Some sources say not really.

Sure, Trump knows Giuliani is back on the clean-up tour, but this much is clear: Trump wants a TV lawyer to fight for him without worrying about the consequences to his own reputation, and Giuliani fits the bill.

In a way, sources say, that works for the other attorneys, too: Rudy is willing to go almost anywhere to change the conversation. He's the guy who will go out there and drop some new bombshell so the President can protect himself. And he's willing to double back when he double-speaks. In other words, he's willing to confuse and cause chaos when that is what is warranted. And even when it's not.

Consider this example: Early on in his tenure as part of Trump's legal posse, Giuliani surprised Sean Hannity by saying the President had repaid the $130,000 to Stormy Daniels and that it was "funneled through a law firm," so there were no campaign finance violations. Never mind that the President had just denied knowing anything about any payments. So, was this a mistake? No, said Giuliani. He had discussed the matter with the President himself.

"The strategy is to get everything wrapped up and done with this so that it doesn't take on a life of its own," Giuliani told CNN after that Hannity interview in early May.

Translation: law enforcement was probably aware of the truth, anyway. So get it out there and give up the charade.

A job for Giuliani.

In that case, Rudy may have had a plan to try and protect the President. But it doesn't always work that way. Recently, when Giuliani was forced to walk back his statements on Trump's conversations with Michael Cohen about Trump Tower Moscow, it was all about clean-up. In an interview with The New York Times, he appeared to be actually quoting the President when he said, "The Trump Tower Moscow discussions were going on from the day I announced to the day I won."

The real lawyers then swooped in behind the scenes to walk it back -- no doubt concerned about their written answers to the special counsel on the topic -- with Rudy now saying he wasn't really "quoting" the President, per se, but was rather giving a "hypothetical" statement. No one was thrilled, and the President knew that clean-up was required. "He's not pissed," Giuliani told Dana Bash, speaking of the President. "He just wants it clarified. He understands how these things happen. It happens to him all the time."

Giuliani runs a close second to the boss. "It's hard to know whether Giuliani is crazy like a fox or just crazy," says CNN legal analyst Michael Zeldin. "His comments keep stories in the headlines when they might have receded. And if what he says contradicts anything the president has written in responses to Mueller, he opens the president up for more questions...and perhaps a subpoena for oral testimony."

Small wonder that parsing Rudy has become a national pastime.

When he recently told CNN's Chris Cuomo that "I never said there was no collusion between the campaign or people in the campaign ... I said the President of the United States," networks everywhere went to the video evidence that, indeed, he had said there was no collusion between the Russians and the campaign. Not to mention that the President has tweeted the "no collusion" line dozens of times.

So was there a reason to do it? After it became clear that ex-campaign chairman Paul Manafort had shared internal polling with two Kremlin supporting oligarchs while he worked for Trump, someone had to, er, clarify the record. Two efforts of clean-up later, and this much was clear: Trump is the client. While he had no contact with Russians, Giuliani said, "I can't possibly say no one had contact about something or in some way." But not Trump.

And that's why Trump hasn't fired Rudy Giuliani. Could he? Sure. Could he "layer" him, as one source suggested, limiting his TV time? Of course. But then you might ask what would Rudy do if he's not on TV? Whatever happens, don't forget: Trump likes Rudy. They go back a long way. They speak the same language. They're both fighters from New York.

Does the President share things with Giuliani that he doesn't share with the other lawyers? We don't know, but it's possible. Does Giuliani screw up? Yup, he does, and that irks the President. But in Donald Trump's view of the world, Giuliani has one trait that matters above all else: loyalty. "I am not lying for the President," Giuliani told Bash. "But I think he (Trump) is being unfairly treated and somebody has to point that out and has to defend him."

Rudy Giuliani is only too happy to answer the call. Especially when Donald Trump is at the other end of the line.