More than $1.6 billion has been spent or booked on TV ads in a dozen Senate races, with $3 out of every $4 being spent in six states — Georgia, Pennsylvania, Arizona, Wisconsin, Nevada and Ohio, according to an NPR analysis of data provided by the ad-tracking firm AdImpact.Outside groups, including those closely tied to Senate Minority Leader Mitch McConnell, have poured in nearly $1 billion to buoy GOP Senate candidates. Eighty-six percent of the money going toward pro-GOP TV ads is coming from these outside groups, compared to 55% for Democrats.This episode: voting correspondent Ashley Lopez, political correspondent Susan Davis, and senior political editor and correspondent Domenico Montanaro.*Support the show and unlock sponsor-free listening with a subscription to The NPR Politics Podcast Plus. Learn more at plus.npr.org/politics) ***Connect:**Email the show at [email protected])Join the NPR Politics Podcast Facebook Group).Subscribe to the NPR Politics Newsletter).Learn more about sponsor message choices: podcastchoices.com/adchoices)NPR Privacy Policy)