I'm here to tell you different. I've been in and around politics for nearly half a century. I've followed newspaper and TV endorsements of half a dozen papers and comparable number of TV stations over four hundred elections and several thousands of candidates, initiatives and propositions.
I've never seen an endorsement that had any influence whatsoever. For every case where every press outlet endorsed a candidate and he won, there are an equal number where his opponent won. The same is true for initiatives and propositions. The only conclusion is that endorsements don't matter, that includes union endorsements and party endorsements. Sorry. I've tested this several times with statistical tests.
So then, it must be reasonable to conclude that money spent on a campaign is what makes a difference. Again, the answer is "generally no."So what does matter in any campaign?
*(1) Some realities about politics such as the normal turnout in a specific election, the party allegiance of the registered voters, incumbency etc.*(2) In local city or regional elections there are 30+ trusted opinion leaders who's private communications determine the election outcome... all done via informal networks.
*(3) What the voters perceive to be the real nature of the candidate or the issue.
*(4) Fortuitous circumstances such as political waves, dominant issues and unexpected public events.