Most definitely yes. Its pretty easy to spot too. Want to know who will win the election? Its the candidate that the major news networks allow to control the message. This election, that is Bernie Sanders. They allow him to say what ever he wants without critical analysis. And by critical analysis, I mean, asking him questions and not allowing him to divert the conversion.
People turn to the news and the media to better inform themselves on candidates and political issues so it definitely affects the national elections. In America, we have Fox News, who is notorious for having biased Right Wing views and they have a die hard fan base who pretty much agrees with everything they say. There are some liberal news organizations too, but they don't have the pull of Fox. (or that Fox once had)
The media controls a lot of the information that is provided to individuals about election candidates, and therefore has a lot of power to influence elections. Media outlets can choose what to say about candidates to sway public opinion for or against them and can even choose which candidates can participate in broadcast debates. They can choose which commercials to run and when, allowing candidates more or less publicity and ultimately have a lot of control on election outcome.