Transcript for A look back at the Bush presidencies

Good to be with you. President George W. Bush posted a photo of his parents on Instagram overnight saying, George H.W. Bush was a man of the highest character and the best dad a son or daughter could ask for. And the bush family has cemented their name in American politics. John Adams and John quincy Adams are the nation's only other father and son duo to hold the highest office. ABC's Amy robach looks back at the bush presidencies. Reporter: They shared a unique and rare bond, not just as father and son, but as former presidents, only the second such pair in U.S. History affectionately known as 41 and 43. I accept your nomination for president. I proudly accept your nomination. Reporter: Each campaign for the other during their respective bids for the presidency. This son of ours is not going to let you down. He's going to serve with great honor all the way. I, George Herbert walker bush, do solemnly swear. I, George walker bush, do solemnly swear. Reporter: And eight years after his own pain Felton re-election defeat, a father watched his son win the nation's highest office. I want to thank my dad, the most decent man I have ever known. All my life I have been amazed that a gentle soul could be so strong. Dad, I am proud to be your son. Reporter: But the men shared much more than just time in the white house. I have no choice but to drive Saddam from Kuwait by force. We will not fail. Reporter: As both were wartime presidents against a common enemy, Saddam Hussain. Coalition forces have begun striking selected targets. Reporter: The younger bush leading the 2003 U.S. Invasion of Iraq 12 years after his father declared war on the me country. I don't know that it's changed him. He's a man of strength, of character. He's a strong person. Tell me which is harder, to be president and to be subjected to the criticisms that come with the job or to watch your son be subjected to those same criticisms? It's not a close call. Far worse is watching your son come under fire. Far worse. When you're responsible for your own acts, when you're the president, you take it. Now I'm just a sentimental father who doesn't like it when his kids are criticized. Reporter: Father and son at Barbara Bush's funeral, our 43rd president dutifully pushing our 41st in his wheelchair but more than that a son supporting the father he revered. He served our country in many ways. Each time he has done so with integrity and courage and dignity. He showed the world and future generations how to lead and reject tyranny's ugly character. His leadership was distinguished by the quiet everyday acts of principle and in character that is still -- instilled in others the belief that they too make a difference. He was a great president. But more importantly he's the best dad a fella could have. President George Bush. That was our Amy robach reporting there. It was interesting to hear him reflect back and as a father and being more hurt by the criticism his son was receiving than he was receiving.

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