Lyndon B. Johnson is remembered in history as a larger-than-life president whose uncanny powers of persuasion allowed him to accomplish monumental legislative feats and bring sweeping changes across the country.
But in a new book "The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society," historian and author Julian Zelizer offers a critique to the Johnson mystique -- arguing that "we exaggerate how much power" the 36th president actually had.
"We have this image that he could twist any arm he wanted, get any bill through Congress," Zelizer told "Top Line" in an interview. "But that doesn't really capture the moment of the 1960's when he got a lot of these bills through, and I think it does a disservice both to the current president and others who are compared to him and to Johnson in that period of time."
While Zelizer maintains that Johnson was a "great president," he points out that many of his greatest accomplishments on civil rights were aided by a confluence of interests with the civil rights movement.
The debate over Johnson's legacy has flared up because of the movie "Selma," which portrays Johnson's role in the events that lead to the eventual signing of the Voting Rights Act of 1965. And though Zelizer said the movie gets a lot right, "it gets LBJ wrong."
"LBJ, by early 1965, was fully on board with voting rights," Zelizer said. "He was working on it behind the scenes; he had his people negotiating with members of Congress before the Selma marches ever happened. He wasn't prepared to send a bill -- and the movie's right -- King wanted it earlier. But it portrays him as indifferent; it portrays him as obsessed with surveillance on Martin Luther King. And that was not LBJ at that period."
Zelizer also sought to debunk a common critique that President Obama's presidency has been less effective than Johnson's. Instead, he says the two presidents share many of the same challenges.
"The election of 2008 created grassroots momentum for some kind of change, rejection of the status quo; it temporarily created a Congress where Democrats had control, including on health care, where they were really able to push the bill through even with strong Republican opposition," Zelizer said. "When that closes down in 2010, President Obama's not been very successful."
The arc of Obama's presidency is in many ways "very comparable" to what Johnson faced, Zelizer said, when the 1966 midterms gave Republicans the upper-hand in Congress. Following the election, Zelizer said Johnson felt "defeated" and became defensive.
"He's defending himself against conservatives who are saying Vietnam's a mess, 'You're not tough enough,' and liberals who are saying, 'You're too tough,'" Zelizer said. "So, by March of 1968, he surprises the whole nation, he doesn't even tell his most of his advisers; he goes on TV and says ‘I'm not going to run again,’ and he feels that that's the best for the country."
Zelizer also suggested the Johnson of the 60's might not have been as successful if he were president in the 21st century.
"He'd certainly have to clean up his stories -- some of the stories on the phone conversations are very colorful and certainly not for public consumption," Zelizer said. "And in an age of Twitter and social media, if any of this got out, it would probably be devastating."
For more of the interview with Zelizer, and to hear his favorite story about Johnson, check out this episode of "Top Line."
ABC News’ Richard Coolidge, Tom Thornton, Chris Carlson, and Bob Bramson contributed to this episode.