If Donald Trump really has spent hardly anything on his campaign, what does that say about advertising?

"I've spent no money, and I'm number one."

Trump and his team realised that in 2015, he could generate apparently huge support simply by saying controversial stuff about immigration, foreign affairs and even his opponents (Youtube)

2016 is a presidential election year in America, which means literally billions of dollars more spent on television advertising. WPP's Kantar Media, which tracks political advertising, predicts around $4.4bn will be spent on TV for this election, up from $3.8bn in the 2012 campaign, which of course Barack Obama won. Across the pond however, there is growing doubt about whether this largesse actually makes much difference to the outcome.

Obama's campaigns in both 2008 and 2012 were characterised by a combination of digital and social media comms, local events, brilliant PR and traditional ads. And Donald Trump's rise as the leading Republican nominee has thrown the efficacy of TV ads further into question. The fact is that the Trump campaign has so far spent almost nothing on media, while some of the least successful candidates, such as Jeb Bush have spent the most.

Trump and his team realised that in 2015, he could generate apparently huge support simply by saying controversial stuff about immigration, foreign affairs and even his opponents. The US (and international) media have lapped it up - as apparently have Republican primary voters, among whom he has 35 per cent support. He is quoted as saying:

"I've spent no money, and I'm number one."

But before we call the swan song on political TV advertising we should look again at Kantar's estimates. During the last week in December even Trump announced: "We're going to start spending a lot of money. I'm looking to win everything - we want to run the table."

The fact is that unless politicians adopt this approach, the American media will not take their bids seriously. And hard-hitting paid-for campaigns tend to generate lots of free PR.

All that said, some are now predicting 2016 will be peak election in TV ad terms. Spend on digital comms is expected increasingly to eat away at traditional budgets, as the younger generation pays even less attention to TV, and more to their phones and peer networks.

Television remains king for now, but the high spend in 2016 masks major trouble ahead for Madison Avenue, the old media establishment and complacent Mad Men anywhere.