Trump said he is in good company as a former Democrat.
He joins Ben Carson and Rick Santorum as the only GOP presidential candidates in favor.
The poll showed neighboring Gov. Scott Walker of Wisconsin dropping even further.
Peter Sullivan 09/01/15 05:53 PM EDT
The presidential candidate has attacked drug companies for "outrageous profits."
The new rules likely will help Carly Fiorina get on the stage.
The visits from the 2016 hopefuls come as the island faces a $70 billion debt crisis.
The senator has repeatedly taken issue with Trump's "Make America Great Again" campaign slogan.
Coons said Biden deserves the "time and the space" to make a decision on whether to run.
O'Malley said he was "flattered" by the email.
Trump sought to mend fences with the prominent Hispanic business leader.