Former Florida Governor Jeb Bush has officially launched his US presidential campaign, promising to "run with heart" and "take nothing and no one for granted". Mr Bush, the son and brother of two former presidents, spoke in his hometown of Miami, Florida. Recently released campaign branding leaves behind his surname, which some see as a political liability. Polling suggests he has yet to dominate a wide field of Republican candidates. Speaking in both English and Spanish, Mr Bush used his speech to appeal to a broad swath of the US electorate - of which minorities have become increasingly more important - not just the Republican's conservative base. Much of Mr Bush's remarks were dedicated to his record as the former governor of Florida, during which time the state enjoyed economic growth. However, his speech was interrupted by at least one heckler, forcing Mr Bush to improvise a response that included a denunciation of President Barack Obama's immigration reforms. In a video released ahead of the speech and played at the event before he spoke, Mr Bush pledged to protect the most vulnerable and remove barriers to social mobility. In the video, titled The Greatest Century, he said: "I see a great country on the verge of its greatest century, and I'm ready to lead." Although his campaign became official on Monday, it's been no secret for many months and his team is well on the way to raising a $100m war chest. During a tour of Europe last week, Mr Bush warned he would not waver from his core beliefs, even if some are unpopular in his party. "I'm not going to change who I am," he said. "I respect people who may not agree with me, but I'm not going to change my views because today someone has a view that's different." In a separate video, called Making A Difference, he champions the rights of women, ethnic minorities and the disabled. "My core beliefs start with the premise that the most vulnerable in our society should be in the front of the line and not the back,'' he says. "What we need is new leadership that takes conservative principles and applies them so that people can rise up." A Spanish language video was also released, demonstrating his strong Hispanic links - his wife Columba is Mexican and he speaks Spanish well. But in recent weeks he has found himself on the defensive over the Iraq War - led by his older brother, President George W Bush - as he stumbled to clarify his position. The issue brought into focus the problems he may face over his famous surname and the baggage that comes with it. He becomes the 11th Republican to declare, with Wisconsin Governor Scott Walker and Florida Senator Marco Rubio among his biggest rivals. On the Democratic side, Hillary Clinton is the clear frontrunner. This raises the possibility in 2016 of another Clinton-Bush race like that of 1992, when Mrs Clinton's husband Bill beat Jeb Bush's father, President George HW Bush.