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.
AFL-CIO chief Richard Trumka said there was still time for Biden to enter.
The 2016 presidential contender is walking back talk of a northern border wall.
Bush's campaign has released a video on the “liberal things that Trump believes.”
Julian Hattem 09/01/15 11:27 AM EDT
The life of a jet-setting diplomat is rather tame, Clinton's emails suggest.
Mario Trujillo 09/01/15 11:03 AM EDT
Steve Wozniak gave a boost to Bernie Sanders's presidential campaign on Tuesday.