Bloomberg, Sensing an Opening, Revisits a Potential White House Run

Michael R. Bloomberg has instructed advisers to draw up plans for a potential independent campaign in this year’s presidential race. His advisers and associates said he was galled by Donald J. Trump’s dominance of the Republican field, and troubled by Hillary Clinton’s stumbles and the rise of Senator Bernie Sanders of Vermont on the Democratic side.

Mr. Bloomberg, the billionaire former mayor of New York City, has in the past contemplated running for the White House on a third-party ticket, but always concluded he could not win. A confluence of unlikely events in the 2016 election, however, has given new impetus to his presidential aspira