Steve Kornacki previews generational change fights in Massachusetts primary

Voters are casting ballots in the Massachusetts primary elections. NBC News Chief Data Analyst Steve Kornacki previews the key races to watch as several incumbents face challengers calling for generational change. For more context and news coverage of the most important stories of our day, click here: https://www.nbcnews.com » Subscribe to NBC News: http://nbcnews.to/SubscribeToNBC » Subscribe to Here's the Scoop podcast: https://www.nbcnews.com/heres-the-sco... » NBC News App: https://apps.nbcnews.com/mobile » Breaking News Alerts: https://link.nbcnews.com/join/5cj/bre... » Visit NBCNews.Com: http://nbcnews.to/ReadNBC » Find NBC News on Facebook: http://nbcnews.to/LikeNBC » Follow NBC News on Twitter: http://nbcnews.to/FollowNBC » Follow NBC News on Instagram: http://nbcnews.to/InstaNBC #massachusetts #news #politics