WEST MIAMI, Fla. — For years, Senator Marco Rubio struggled under the weight of student debt, mortgages and an extra loan against the value of his home totaling hundreds of thousands of dollars. But in 2012, financial salvation seemed to have arrived: A publisher paid him $800,000 to write a book about growing up as the son of Cuban immigrants.
In speeches, Mr. Rubio, a Florida Republican, spoke of his prudent plan for using the cash to finally pay off his law school loans, expressing relief that he no longer owed “a lady named Sallie Mae,” as he once called the lender.
But at the same time, he splurged on an extravagant purchase: $80,000 for a luxury speedboat, state records show. At the time, Mr. Rubio confided to a friend that it was a potentially inadvisable outlay that he could not resist. The 24-foot boat, he said, fulfilled a dream.
Among the serious contenders for the presidency, Mr. Rubio stands out for his youth, for his meteoric political rise — and for the persistent doubts about his financial management, to the point that Mitt Romney’s presidential campaign flagged the issue when vetting Mr. Rubio as a possible running mate in 2012, interviews show.