“Not only in 2012, but in every election for which the data exists (from 1980 to 2012)…the link is clear: when the Democrats spend more than Republicans, their candidates win. When Republicans spend more than Democrats, they win.”
If the pattern holds, Clinton is a shoo-in. Apart from their more extensive network of field staff, the Democrats have planned $100 million in TV advertising over the next several months compared to a paltry $1 million so far booked by the Trump campaign:
http://www.nbcnews.com/politics/2016-election/team-clinton-poised-98-million-ad-blitz-n621741).
However, the ordinary patterns are being upset as political instability mounts, and maybe the “Bradley effect” will be sufficient for Trump to overcome his polling and spending deficits. I doubt it, but that’s the concern expressed here:
https://www.thenation.com/article/are-hillary-clintons-strong-poll-numbers-misleading/