His authorship of a controversial immigration bill hurt him among the party’s conservative base, including Republicans in his own state. Rubio has since softened his position on the issue, and worked to elect new Republicans from Iowa, Arkansas, and Colorado to the Senate who opposed his bill. It seemed, for a moment, like Rubio had turned the page on the controversy and would be Florida’s sole candidate, but then Jeb Bush stepped in the spotlight. The Republican establishment in the state quickly declared their allegiances to the former governor, raising questions about Rubio’s ability to raise money in his own backyard and leading to conjecture that he would instead run for governor in 2018.

Also tempering enthusiasm is that Rubio’s recent moves—from the gathering of donors and bundlers to a string of fundraisers this month in California, Texas, and Chicago—overlap with a promotional tour for his second book, American Dreams: Restoring Economic Opportunity for Everyone. Speculation about a presidential campaign, it turns out, can be very good for book sales.

Writing books can help clarify one’s message, and to boosters like former Florida Republican Party Chairman Al Cardenas, Rubio “did a great job setting forth his vision for America” during a 45-minute speech to the larger crowd of donors last Saturday. “I am certain he has not made a decision,” Cardenas said about whether Rubio may run for president. “I am also certain that his staff really wants him to jump in.”