According to nationwide opinion polls in early 2015, Clinton was the front-runner for the 2016 Democratic presidential nomination.[6][7] She did face other several primary election challengers.[4][5] A Franklin Pierce University/Boston Herald poll in mid-August 2015 showed Senator Bernie Sanders with a 44-37 lead over Clinton in the first-in-the-nation primary state of New Hampshire.[8] And, in August 2015, Vice President Joe Biden was reported to be seriously considering a possible challenge to Clinton.[9]
The Clinton campaign had planned a delayed announcement, possibly as late as July 2015.[10][11][12] Her team decided to make the announcement earlier because of publicity about Clinton's use of a private email server while Secretary of State.[13] Clinton made her official announcement on the following Sunday, April 12, 2015.[14][15]