As of this writing, Clinton only beats two potential Republican candidates in the average national polls at Real Clear Politics: Donald Trump by 2.2 point margin and Marco Rubio by just 6-tenths of a percent. Understand, both these leads are within the margin of error of around 3 points. Also understand that these leads are a result of a single NBC News/Wall St. Journal poll conducted from 10/25 to 10/29 that heavily skewed the numbers in favor of Hillary Clinton. For example, this is a screenshot for the Real Clear national match-up between Hillary and Marco Rubio:
Note: Click on either image to enlarge for clearer viewing
Among all other Republicans, Hillary loses; with Ben Carson leading with a 5.2 point spread win.
It is almost a year away from the Presidential election and a lot could happen. But, the belief by many Democrat pundits that Hillary will get the nomination and win the election isn't that certain.
Real Clear Politics: 2016 Presidential Polls: http://www.realclearpolitics.com/epolls/2016/president/2016_presidential_race.html