Jeb Bush was preparing to release the emails he sent and received as Florida governor when he was excoriated by a letter-writer to The Miami Herald.

The headline: "Don't trust Jeb Bush with the power of the presidency."

The subject of many of the emails was Terri Schiavo. The letter-writer was her husband, Michael.

Bush's effort to stop Michael Schiavo from removing his brain-damaged wife's feeding tube was a defining moment of Bush's time in office.

Bush, a devout Catholic, sided with Terri Schiavo's parents in the end-of-life dispute and reached for unprecedented authority to intervene. Michael Schiavo said his wife did not want to be kept alive artificially.

As Bush moves toward a run for president in 2016, Michael Schiavo has re-emerged, promising to campaign against Bush and remind voters about the ex-governor's role in the matter.

"I will be very active," Schiavo, a registered Republican, told The Associated Press in an interview. He said he plans to back Democrat Hillary Rodham Clinton, should she run.

To Schiavo, Bush "owes the public, along with myself, a huge apology."

Asked last week about the case, Bush told the Tampa Bay Times: "It's appropriate for people to err on the side of life. I'm completely comfortable with it."

Bush's recently released emails are part of his attempt to define himself on his terms. Many of the emails deal with the Schiavo case.

"Please know that I respect the opinions of those who disagree with the actions I have taken," Bush wrote a constituent in 2005. "This is a heart-wrenching case, and I have not taken any action without thought, reflection and an appreciation for other points of view."

Friends and advisers to Bush say his actions were driven largely by his faith, and they believe his effort to keep Schiavo alive - despite wide public disapproval - illustrates principled leadership. That could help in early presidential voting states such as Iowa and South Carolina, where social conservatives hold significant sway in the nominating process.

"Jeb felt strongly from a personal standpoint that she should be given a chance," said Al Cardenas, former chairman of the American Conservative Union.

Terri Schiavo's parents, Bob and Mary Schindler, asked Bush for help. They disputed the diagnosis that she was in a "chronic vegetative state" and said that their daughter, as a Catholic, would not want to be taken off life support.

"For Mr. Bush, it was clearly about doing the right thing," said David Gibbs, the Schindlers' lead lawyer. "He knew the easiest thing would be for him to avoid the issue and just be the governor. But he felt in principle that one disabled woman was worth his time and attention. He showed genuine compassion."

Bush first intervened in 2003 as the Schindlers' legal appeals were coming to an end. A judge's ruling that Michael Schiavo, Terri's legal guardian, could remove her feeding tube had withstood years of court challenges. But the governor took the unusual step of writing the judge and asking him to assign a different guardian.

"I normally would not address a letter to the judge in a pending legal proceeding," Bush wrote. "However, my office has received over 27,000 emails reflecting understandable concern for the well-being of Terri Schiavo."

His request was rejected.

On Oct. 21, 2003, six days after the feeding tube was removed, the GOP-controlled Legislature passed a one-page bill granting the governor the power to order the tube reinserted. Bush signed it into law, and a police-escorted ambulance moved her from a hospice to a hospital, where the tube was put back in.

"I honestly believe we did the right thing," Bush wrote a constituent who supported the move.

Others weren't so sure, including some of the Republicans who shepherded the measure through the Legislature. "I keep thinking, `What if Terri Schiavo really didn't want this at all?'" the late Jim King, then Florida's state Senate president, said at the time.

Nearly a year later, the Florida Supreme Court ruled the law unconstitutional. Bush appealed to the U.S. Supreme Court, was rejected and asked Congress to intervene. Lawmakers, including then-Sen. Clinton, voted to give Terri Schiavo's parents legal standing to appeal anew in the federal courts, which then rejected their case.

In a last-ditch effort, Bush tried to have the state Department of Children and Families take custody of Terri Schiavo, based on allegations that she had been abused by her husband and caregivers. The move was rebuffed by the presiding judge.

On March 31, 2005, Terri Schiavo died.

Even after that, Bush raised questions about Michael Schiavo's involvement in his wife's initial collapse and asked that a state prosecutor revisit the case. "Jeb Bush had no right to do what he did," Michael Schiavo said in his letter to the newspaper.

The prosecutor concluded there was no evidence of wrongdoing.

"Voters should consider what someone who used the power of government to hurt so many would do with the power of the presidency," Schiavo wrote.

In a statement upon Terri Schiavo's death, Bush said he joined those in Florida and around the world who were "deeply grieved by the way Terri died."

"I remain convinced, however, that Terri's death is a window through which we can see the many issues left unresolved in our families and in our society. For that, we can be thankful for all that the life of Terri Schiavo has taught us."