DES MOINES, IA — Former Florida Gov. Jeb Bush has recently begun making more high-profile public appearances, leaving his big donors and allies tantalized by his promise to decide “in short order” whether to run for president.

Bush is scheduled to give the commencement address Monday at the University of South Carolina during his second visit in recent months to the state that’s set to host the first presidential primary in a southern state in the 2016 campaign season.

As the son of one president and brother of another, Bush has the power to transform the 2016 contest like no other Republican. He can tap into his family’s vast political network, and his campaign would attract strong support from major donors and widespread media attention.

But his supporters are struggling to understand what Bush’s actions mean and whether they can predict his political intentions.

Bush spent much of the recent midterm campaign out of the public eye. But the address at South Carolina will be his fourth high-profile speech in recent weeks. That includes an appearance before corporate executives in Washington, where he called for his party to embrace an immigration overhaul and to focus on governing. He also said would make the call on running for president “not that far out in the future.”

In an interview with ABC’s Miami affiliate WPLG-TV, Bush said he was in the process of writing an e-book about his time as Florida governor and that it would come out in the spring. At about the same time, he will make public about 250,000 emails from his time in office, in an effort to promote transparency and to “let people make up their mind.”

Bush said going through the material has reminded him that “if you run with big ideas and then you’re true to those ideas, and get a chance to serve and implement them and do it with passion and conviction, you can move the needle. … And that’s what we need right now in America,” he said in the interview set to air Sunday.

But at the same time Bush has been expanding his private equity business, and advisers insist he’s not courting a political staff in Iowa and New Hampshire, even as other would-be candidates assemble their 2016 campaign teams in the early voting states. Those are signs he might not run.

About all anyone can say for certain is that, as Bush himself has said, he’s still thinking about it.

“He’s begun the journey. How long it will take him, I don’t know,” said Al Cardenas, a longtime Bush friend and former chairman of the American Conservative Union. “People are interpreting activity to conclude that he’s closer to running. I’m not of that school.

“I hope he runs, but I believe the activity is based on getting serious.”

Slater Bayliss, a longtime Florida-based Bush aide who helps lead a political action committee founded by Bush’s sons, met with strategists in Iowa during a late November trip to his native state. But Bush’s spokeswoman, Kristy Campbell said Bayliss’ trip to Iowa was not authorized by Bush and unrelated to his decision-making.

The same week Bayliss met with Iowa Republicans, Bush was named chairman and manager of a new private equity fund, BH Global Aviation. As first reported by Bloomberg, the offshore fund raised $61 million in September.

Bush’s team described the investment as an expansion of an existing, and previously reported, private business, which he would review should he run. Most recent presidential candidates, including private equity investor Mitt Romney, formally cut ties with their business interests years before running.

Bush “is very proud of his investment work to grow companies,” Campbell said, adding that there is no part of his business interests “that would hinder a run for president if that is the decision he makes.”

There is no shortage of pressure on Bush to get into the race, including from members of his family. His older brother, former President George W. Bush, has encouraged his brother to enter the 2016 contest.

“He knows I want him to run,” Bush told CNN recently. “If I need to reiterate it, I will: ‘Run, Jeb.’ I think he’d be a great president.”

STEVE PEOPLES, Associated Press
THOMAS BEAUMONT, Associated Press___

Peoples reported from Washington. Associated Press writer Michael Mishak in Miami contributed to this report.