One such moment came after Iraqi leader Saddam Hussein fell after the second Gulf War in April of 2003.

In an e-mail to his son, the elder Bush recalled comments he made to friends saying, "I shamefully choked up, the tears tumbling down my aging cheeks. I was embarrassed; but then I realized that I shouldn't worry if people see this visible manifestation of a father's concern, a father's love. It was pride, yes, but it was also an overflowing of joy from all that you have given your mother and me over the years..."

Bush continued, "...Bar (Barbara) and I are at your side. I hope you can feel it. We will stay out of the way, but I am there beside you, my heart overflowing with happiness on this day of vindication."

When his son was seeking re-election in 2004, the elder Bush said he was hungry for any information about the race and received a briefing the day before the election from his chief of staff.

"Though 43 was still leading by a thin smidgeon in many of the states, some of the important ones had slipped into a tie or into a small negative," Bush wrote in a letter to Sidey. "This, of course, caused by aching duodenum to throb, to pulsate, to hurt."

And the elder Bush recounted how he was watching television news the previous Sunday, and heard some political pundits call his son a "liar."

"The whole atmosphere is horrible and for this loving Dad it is impossible," the father wrote. "I cannot run away and hide."

He recounted that he was a "nervous wreck" on Election Day. "I feel like I have been hit squarely in the gut -- hard," the elder Bush wrote.

The day after the younger Bush won re-election he told Sidey his son "...asked me to come over to the Oval Office. I threw on my clothes and went over there. The two of us sat alone in that historic office. For me it was magic."

Later the father recounted how he stood with his son on the White House putting green.

"To myself, I was saying, 'I wish I could help this son of ours. I wish I could do something to help ease the burden, a burden incidentally that he never ever complains about. But I cannot. I am an old guy. My experiences are out of date. Perhaps my instincts aren't as good as I once thought they were,'" the elder Bush said. "George W. said to me, 'Dad, do you realize that this is the first time since 1988 that a President has won with a clear majority of the vote?' My mind raced back to my win over (Democratic nominee Michael) Dukakis in 1988. Who would have thought back then that I would be bonding with my own son in that manner?"

The elder Bush ended the letter by writing, "Victory. How sweet it is."