"I love my father and my brother. I admire their service to the nation and the difficult decisions they had to make," he said, referring to the 41st and 43rd presidents, George H. W. Bush and George W. Bush. "But I am my own man, and my views are shaped by my own thinking and own experiences."

In a question and answer session after the speech to a Chicago thinktank, Mr Bush conceded that under his brother, "there were mistakes made in Iraq", including that the belief that Iraq held weapons of mass destruction, the basis for the United States' invasion, "turned out not to be accurate."

Earlier it was revealed that Mr Bush has consulted many of his father's and brother's foreign policy advisers, including Paul Wolfowitz, a key architect of the invasion of Iraq, and James Baker, a former secretary of state and chief of staff to presidents Ronald Reagan and George H. W. Bush.

In the speech, Mr Bush positioned himself as a hawk, advocating for increased military spending and saying his political coming of age been during the 1980s, when his father and Ronald Reagan had pursued a policy of "peace through strength."

"Having a military that is equal to any threat ... makes it less likely that we will need to put our men and women in uniform in harm's way," he said.

He called for closer international ties, including with Australia, Korea and Japan, and a strengthened NATO.

He said the US had historically been a source of global leadership, peace and stability because presidents of both parties had accepted the responsibilities of United States' power. But he said the current administration was inconsistent and indecisive.

"The problem is perhaps best demonstrated by this administration's approach to Iraq," he said, before correcting himself and referencing Iran.

The invasion of Iraq and the Bush family legacy are hurdles Jeb Bush will confront in any campaign for the White House.

"Governor Jeb Bush has a family problem," said Peter Brown, assistant director of the Quinnipiac University Poll in a statement accompanying new polling released on Wednesday morning. "Many voters don't like him coming from a family of presidents."

By contrast, fewer voters were put off by the family ties of the leader of presumed Democratic candidate, Hillary Clinton, wife of former president Bill Clinton, the poll found.

In Iowa, 35 per cent of those polled said they're less likely to vote for Bush because of his family, compared to only 18 per cent who said that's the case for Clinton.

Jeb Bush remains the early leader of a crowded field of presumed Republican contenders, including the combative New Jersey Governor Chris Christie, the Tea Party senator from Texas Ted Cruz and the Libertarian congressman Rand Paul.