Jeb Bush in the running: Is he or isn't he?

Jeb Bush's big donors and allies are tantalized by his promise to decide "in short order" whether to run for president.

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

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 South's first presidential primary.

On the eve of the appearance, he said he plans to release an electronic book early next year along with roughly 250,000 thousands of emails from his time as governor.

Surely, that's a sign the former Florida governor is in.

Bush also is expanding his private equity business, and advisers insist he's not courting a political staff Iowa and New Hampshire, even as other would-be candidates assemble their 2016 campaign teams in the early voting states.

Surely, that's a sign he's out.

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."

Bush has said he expects to make a decision by the end of the month.

As the son of one president and brother of another, he 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.

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 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.

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.

Former Iowa Republican Party Chairman Chuck Larson was among those who discussed with Bayliss the state's political trends, policy issues and how the state might react to a Bush campaign.

"If Jeb Bush decides to run for president, I believe he will be incredibly well received by conservatives in Iowa," Larson said.

Bush's spokeswoman, Kristy Campbell, like other advisers, said the meetings were unauthorized and unrelated to his decision-making.

She said Bush "has not yet made a decision on whether he will pursue a run in 2016, and has certainly not dispatched anyone to meet with Iowa leaders," Campbell said.

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."

Still, associates say that the family support and a growing public profile should not necessarily be taken as a sign of anything.