TN-Sen: Koch network makes massive investment in tight Senate race to defeat Democrat Phil Bredesen

Americans for Prosperity, the political advocacy group funded by David and Charles Koch, has launched a massive ad buy in Tennessee against Democratic candidate Phil Bredesen.

Bredesen, the Volunteer State's former governor, is running against Rep. Marsha Blackburn (R). They are locked in a tight battle, one that could prove essential for Republicans to win if they want to retain their majority in the upper chamber.

What are the details?

AFP-Tennessee launched a $2 million ad buy against Bredesen this week, the Tennesseean reported. The ad launches a broadside against the 74-year-old Bredesen for implementing tax increases during his time as Tennessee governor, in addition to lavish upgrades to the governor's mansion under his watch.

"When times are tough, we budget for our families. But when our state's budget was in crisis, Phil Bredesen supported higher taxes on us, higher gas taxes, sales taxes, and more," the ad's narrator says.

"And while we struggled through a recession, Bredesen wasted $9 million taxpayer dollars upgrading his governor's mansion: $4 million on a party cave, gilded bathrooms, and a kitchen worth two Tennessee homes," the narrator adds. "Phil Bredesen lived the life, we paid the bill."

The ad will begin airing Thursday on all broadcast platforms, including digital. It's not yet clear if AFP will initiate another ad buy before November's general election.

Does the ad hold up to the facts?

According to the Chattanooga Times Free Press, Bredesen raised various taxes and fees by nearly $1 billion during his tenure as governor, many of which were "technical corrections."

The biggest taxes included a cigarette tax, which in 2007 was estimated to collect $160 million to $180 million in revenue annually, and a hike in employer taxes to keep Tennessee's Unemployment Trust Fund solvent. That increase amounted to $245 million in 2010.

However, as the Tennessean noted, neither the state's sales tax nor the gas tax technically increased during Bredesen's tenure.

Meanwhile, it's true the governor's mansion underwent a six-year renovation during Bredesen's governorship. The $18 million project, half of which was taxpayer funded, made major safety and aesthetic upgrades to the residential property, which was built in 1931.

One aspect of the renovation project, which the ad referred to as the "party cave," was particularly controversial. Critics similarly referred to the project as "Bredesen's Bunker" at the time.

Bredesen and his wife, Andrea Conte, did not live in the mansion during Bredesen's governorship. They elected to remain in their private Nashville residence.

Bredesen's spokeswoman, Alyssa Hansen, cited these facts in response to the ad.