Former Florida governor Jeb Bush, who has remained on the sidelines since his older brother left the White House with dismal ratings four years ago, has jumped back into the political fray this week with a new book, wall-to-wall television interviews and a round of public speaking engagements. His appearances mark a change in approach for Bush, 60, who has operated as more of a Republican elder statesman since leaving Tallahassee in 2007 but is now clearly considering a run for the White House.