Billionaire Tom Steyer's ad spending

Win or lose, billionaire Democrat Tom Steyer will leave a mark in the history books in his bid to become California's next governor — he's running the most expensive political advertising campaign in the country this year.

1. Frame 1Tom Steyer puts more than $195 million into California's governor election, aiming TV, cable, and radio ads at voters.
2. Frame 2AdImpact's tally makes it the country's most expensive political ad campaign this year.
3. Frame 3His ad buy is more than 20 times Xavier Becerra's as they chase a November spot.
4. Frame 4The flood of TV, cable, and radio spots turns billionaire spending into the campaign's central test.
5. Frame 5Next pressure: whether California voters turn the ad blitz into a November ballot spot.