GARY JOHNSON and JILL STEIN handed the PRESIDENCY TO DONALD TRUMP. Few people knew or cared about either third-party candidate, but enough of them voted to cost Clinton the election. Third-party candidates giveth and taketh away from the Clintons, it seems. Millions of Americans, dissatisfied with both candidates and unwilling to choose between the lesser of two evils, registered their protest by voting for Gary Johnson or Jill Stein, helping hand a number of critical swing states, and the presidency, to Donald Trump.
All of the 3rd party voters if they'd been for Clinton would probably have been enough to tip the scales in her favor. Johnson had no legitimate chance to win the presidency, and even his running mate urged people to vote for her. Trumps margin of victory wasn't very large and I do think the 3rd party votes would have made a difference.
The votes that went to Johnson did not play any significant role in the election. Ultimately, the people who didn't want Clinton to win voted for Trump, but it was still only a drop in the bucket compared to what Clinton would have needed to overtake Trump. Johnson was not a significant player in this election. He appealed to too few to make a difference.
The race was much too close for that. It might have made a differnce if Johnson voters voted for Hillary instead, but there is no garuntee that the would not have voted for Trump if they only had two choices. There was a lot that led to Trump winning and it was not just this.