Former Florida Governor Jeb Bush last night set out his stall to become the third member of his family to enter the White House as president.
Mr Bush pledged to fix America as he launched his bid to become the Republican nominee.
In a video released in Miami, the 62-year-old brother of ex-president George W Bush declared: "I'm ready to lead."
He also promised to protect the country's most vulnerable and remove the barriers to social mobility.
But doubts persist among conservatives in his party.
And early polling suggests that he has yet to dominate a wide field of Republican candidates.
In his latest video, entitled 'The Greatest Century', he strikes a very optimistic note, saying: "I see a great country on the verge of its greatest century, and I'm ready to lead." Although his campaign became official yesterday, 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.
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.