It's a White House job with an indisputable allure — one that didn't exist until the 20th century but has grown into a vital and respected position within the presidency.

Speechwriters are to the man in the Oval Office what screenwriters are to characters in a film. They're the ones who write the lines — in the appropriate voice, of course. After all, it's important to stay true to character or the words just won't sound right.

"The best bet is someone who understands the president and gives expressions that sound authentic in the president's voice," said historian Leo Ribuffo, a professor at George Washington University. "A good speechwriter finds a particularly eloquent way of saying what the president in his heart and mind wants to say."

Former Wall Street Journal editorial writer William McGurn (search) replaced Michael Gerson (search) recently as chief speechwriter for President Bush. Ever since McGurn was accepted into the administration for Bush's second term, White House watchers have been keenly looking for any changes in the president's presentations.

"My job is not the president's image. My job is to give him the words to explain his policy in his language, in his tone of voice, in his logic," McGurn said in an interview with "It's not my speech; it's the president's speech."

Over the years, much ado has been made about whether the speechwriter actually "makes the man" who sits in the Oval Office, in terms of creating his persona.

"In general, writers and journalists tend to overestimate the role that speechwriters play in shaping a president's image," said Jennifer Grossman (search), a former speechwriter for President George H.W. Bush who is now director of the Dole Nutrition Institute.

Most experts agree that rather than the speechwriter making the man, it's usually the other way around — at least in the modern day.

"It's clear that the man makes the speechwriter," Ribuffo said. "The speechwriter is the employee and the president is the president. [The president has] the final say."

But how much "final say" the president demands changes from man to man. In the case of Theodore Sorenson (search) — President John F. Kennedy's chief speechwriter — observers recall that he was involved not only in scripting JFK but also in shaping the popular president into the man he appeared to be to the people.

"There is a dimension to which Ted Sorenson created the persona of JFK — or at least the verbal correlate of the persona of JFK," said cultural expert Neal Gabler, a FOX News Watch panelist and author of "Life: The Movie." "Sorenson and Kennedy were very, very close. They worked in conjunction to create the image of the president."

Added historian Keith Olson, a professor at the University of Maryland: "Ted Sorenson was almost a clone of Kennedy. They thought so much alike. That was as marvelous a blend as you could get."

Though times have changed, the current president has also been tight with his top writers. Gerson, who took another post in the administration, was a Bush favorite, as was another departing member of the team, Matthew Scully (search), according to insiders. The third man in the original Bush writing team, John McConnell, is still scribbling away at speeches.

"Mike [Gerson] left big shoes to be filled," McGurn said. "I'm like the new shoe they have to break in that maybe gives a few blisters."

Grossman — who says she was asked to be on the president's writing staff during his first term but declined because of other job duties — noted that the Gerson-Bush bond could be tough to replicate and predicted the Gerson-McGurn shift will be "challenging."

"This was such a core team for so long, and it was a very distinct style," she said. "Bill McGurn is an excellent writer, but ... sometimes the better writer you are, the more attached you are to your work. Being a speechwriter really requires you to first and foremost support someone else's message. It really requires putting aside the ego."

Gerson is still involved in the process, according to McGurn, and has helped in the transition. McGurn, for his part, is acutely aware of his role as provider of the president's words, rather than writer with a capital "W."

"You really have to serve the president," said McGurn, who works with a team of five other writers and a handful of researchers, fact checkers and assistants. "The president has been very patient with me. He has a brand new guy he didn't know before."

Gerson, a born-again Christian, became known for his heavy doses of religious imagery and language — some overt and some that spoke to the Christian right but weren't necessarily obvious to the general public.

And he shares credit with former staff writer David Frum (search) for the now legendary "axis of evil" turn of phrase in Bush's 2002 State of the Union address. The theme is reminiscent of the famous "evil empire" speech President Ronald Reagan delivered about the Soviet Union that was criticized as hyperinflammatory by some and praised as the catalyst for the Communist bloc's downfall by others.

Thus far, McGurn has penned the Social Security reform pitches President Bush has been giving across the nation, as well as prepared responses to likely questions asked during the recent prime-time press conference about Social Security, Iraq and the War on Terror.

McGurn also took part in the 2005 State of the Union address, but doesn't like to take a lot of credit for it because "I'd just started. ... It was more of a learning process."

Though different commanders in chief handle speeches differently, this president likes to be very familiar with what he's going to say before he says it. His speeches — especially the important ones — will go through several drafts and a lot of tightening, with the final version typically completed ahead of time.

"He's very involved — not at every step along the way, but he certainly will not give a speech he doesn't like," McGurn said. "It goes through a lot of editing. He'll say, 'I wouldn't do this here,' but he hasn't rejected a whole speech."

Bush's predecessor was also very in touch with his own speeches, many of them done by top writer Michael Waldman (search). But President Bill Clinton was more inclined to make last-minute changes to his prose, and he was a master at improvisation, according to those close to him.

"He was incredibly adept at working through something very fast ... committing to memory the parts that he wanted to remember, and then extemporizing the other parts," one Clinton writer is quoted as saying in an article on the process.

Bush's father, on the other hand, was much more hands-off and distant. Grossman said she remembers the elder Bush reading one of her speeches — some remarks for a park opening — for the first time when he actually delivered it.

"He was not that involved [in the process]," said Grossman. "If it was Clinton, he would have been all over that."

The key to effective modern speechwriting, say experts, is not to pen literary prose but to write memorable catchphrases that will resonate.

"None of this is [Charles] Dickens and [Fyodor] Dostoevsky," said Ribuffo. "You come up with a decent line, you underscore points of emphasis."

Speechwriters and their craft are actually a fairly new trend, and presidents up through Woodrow Wilson — a historian and a writer by trade who was in office from 1913 to 1921— basically wrote their own remarks. The first official speechwriter was "literary clerk" Judson Welliver (search), who began working under President Warren G. Harding in March of 1921.

"Presidents didn't give many speeches until the early 20th century," Ribuffo said. "Wilson could be his own speechwriter not only because he was a writer but because he didn't have to give any speeches. Now it would just be impossible."

No president from Thomas Jefferson to William Howard Taft addressed Congress in person, and what are now known as State of the Union speeches used to be written reports.

The speeches of President Dwight D. Eisenhower, who served from 1953 to 1961, filled only 6,618 of the Public Papers of the President, as opposed to those of Clinton, which took up 15,669 pages, according to

And then there were the times that speechwriters were kept hidden behind the scenes, when presidents tried to make it seem as though they wrote their own lines even when they had help.

"For a long period in American history, no one ever knew who wrote the speeches," said Gabler.

In a famous campaign speech, for instance, Eisenhower told voters that "If elected, I will go to Korea" — to fight in a very unpopular war — but the words were actually written by his speechwriter, journalist Emmett John Hughes (search).

And President Franklin Delano Roosevelt liked to keep up the guise that he wrote his own remarks. He was even known to rewrite some of the final drafts in his own hand.

But lines like "the only thing we have to fear is fear itself" — from his 1933 inaugural speech — and "we have learned in this war that we cannot live alone at peace and that ... the only way to have a friend is to be one" — from his 1945 inaugural speech — were actually done by a team of speechwriters.

FDR's personal secretary Louis Howe (search) contributed to the legendary "fear" line in that address, much of which was penned by speechwriter Raymond Moley (search). The later, wartime inaugural was the handiwork of playwright Robert Sherwood, FDR's chief speechwriter for much of his four-term presidency from 1933 to 1945, along with Sam Rosenman.

Even as speechwriters and formal presidential speeches became more common, fewer speeches were given by commanders in chief in the past than are today — and back then television, cable and the Internet weren't around to pick up every word.

Modern-day presidential speeches tend to be less verbal flourish and grandiose rhetoric and more colloquial talk that average Americans can relate to, say experts.

Clinton, for example, is articulate, bright and highly educated — but that didn't always come out in the words he uttered from the podium, where he often struck a more casual, "down-home" tone.

"He was afraid of high-blown rhetoric, afraid of it seeming elitist or separating him as an intellectual, which he was," Gabler said. "[His speeches] were well-written but had no rhetorical flourishes. ... I think that was deliberate."

No matter what the presidential speaking style, the increasing visibility of the leader of the United States of America has spawned a heightened hunger for what's going on "backstage" in Washington. That includes an ever-growing curiosity about who puts words in the president's mouth.

"Speechwriting is the political equivalent of knowing how they do special effects in movies," Gabler said.

And just as cast and crew come and go, Washington insiders say writing-staff changes like the one the current White House has undergone are fairly common nowadays. During the first Bush administration, Grossman remembers, "there was a lot of turnover."

"You get speechwriters who drift in and out of an administration," added Olson.

But just as with Hollywood's cinematic magic, the behind-the-scenes workings of the White House should be so seamless as to seem natural to the public — or the whole thing could fall flat.

In that vein, big changes in the writing staff should be practically invisible to those on the outside.

Otherwise, as McGurn put it, "if people listen to the president and say he sounds different, then I will have failed."