We’re talking about races in Iowa, New Hampshire, South Carolina, and Nevada, where candidates are competing for mere thousands of voters who will be inexpensively inundated with TV ads, political mailers, and front-door conversations with paid staffers. In these decisive contests, the difference between spending $10 million and $15 million yields a minuscule advantage, if any at all.
“You have this tidal wave of money pouring through into these very small spigots,” said Elizabeth Wilner, senior vice president of Kantar Media Ad Intelligence, which tracks campaign spending on TV. “Your sights are just set ever more narrowly, and yet you have this immense amount of money to use and try to reach these people. Eventually, you do hit that end to a return on your investment and it does become waste.”
Certainly, money will still be essential in 2016, and it remains an advantage to have more of it than anyone else. In an extended primary, when the race moves on to larger states for votes held on the same day, an outsized bank account could yet play an important role.

But diminishing returns on cash investments undoubtedly shift the burden of securing the win back on to the candidate and his or her skills…