John Judis writes in The New Republic that Ronald Reagan and George W. Bush "enjoyed great popularity even though polls showed that the public disliked some of their initiatives" because they provided "leadership and not mediation":
Obama's political team appears convinced that by positioning the president as the Great Mediator, they will win over independent voters in the 2012 election... Still, his advisers might want to look at a recent Pew poll that shows Obama losing ground with self-identified independents during the last two months. It just might be that what these and other voters want from a president is leadership and not mediation
In reality, Bush's popularity shot up to stratospheric levels immediately after the 9/11 attacks (86 percent in a September 13 ABC News poll) before he'd even had time to show much leadership. It was a classic rally-around-the-flag response -- exactly what you'd expect given the magnitude of the attacks. The rest of his presidency was a slow decline toward the highest disapproval ratings ever recorded by an American president.
While Reagan also enjoyed high levels of approval at times (most notably, when he was shot, when the economy was booming before Iran-Contra and when he was about to leave office,) he was actually not especially popular either -- his average Gallup approval ratings in office were lower than those of Kennedy, Clinton, Eisenhower, Lyndon Johnson and George H.W. Bush.
Judis has made a practice of overhyping Reagan as a model for Obama. In articles published in March 2010 and August 2010, he claimed that Reagan's communication strategy was responsible for his political success in a poor economy during his first two years in office. However, there is no convincing evidence that Reagan's approval ratings or GOP performance in the 1982 midterms were better than we would have otherwise expected. The same conclusion applies here -- there's no reason to think that "leadership" made Bush and Reagan enjoy "great popularity."