Vulnerable incumbent Sen. Tammy Baldwin, D-Wisc., a lawmaker who has felt the wrath of the extensive Koch network with over $5 million spent against her so far throughout the election cycle, is about to see yet another blitz from the same organization.

Americans for Prosperity announced on Wednesday that they will be launching their new efforts against the Democrats running in Wisconsin, Tennessee and Missouri.

The political network funded by billionaire industrialist Charles Koch is unleashing a multimillion-dollar television and digital ad campaign against three Democrats running for the U.S. Senate in the 2018 congressional midterm elections.

Americans for Prosperity is dedicating $820,000 to its first TV ad in the Wisconsin Senate race, calling for voters to support Baldwin's Republican opponent, Leah Vukmir, a nurse and a member of the state Senate. The ad claims Vukmir has supported middle-class tax cuts while Baldwin voted against the GOP tax bill and backed a $1.3 trillion spending bill.

Another Koch-backed group, the Concerned Veterans for America, is dishing out over $800,000 toward an ad arguing that Baldwin, a member of the Senate Appropriations Committee, doesn't do enough to support veterans.

"With nearly 400,000 veterans living in Wisconsin, and a VA that has been riddled with scandal, our veterans need a strong voice for them in Congress," Dan Caldwell, CVA executive director, said in a press release. "Baldwin's absence and lack of attention at critical moments shows she is not that voice," he added.

For CVA, this is the second campaign against Baldwin since last month, when they published a nearly $1 million ad titled "Empty Chair" which depicts the Wisconsin senator as someone who skips committee hearings and doesn't make enough efforts for veterans.

Baldwin's campaign cited Vukmir's connection to the American Legislative Exchange Council, an entity funded by the Koch's, as the real reason for the billionaire financiers support.

"The Koch brothers are continuing to attack Tammy Baldwin because they know ALEC national board member Leah Vukmir will do their bidding," Bill Neidhart, spokesman for the campaign, said in a statement.

Meanwhile Republican congresswoman Marsha Blackburn could get a boost from Americans for Prosperity in her quest to become Tennessee's next senator. The Koch group is preparing to spend $2 million on a TV and digital ad against her opponent, former Gov. Phil Bredesen.

The ad calls on voters to turn against Bredesen due to a record that AFP says reflects a push for higher state taxes as governor and spending $9 million of taxpayers' money on revamping the governor's mansion.

The Koch network announced their support for Blackburn earlier in the year.

The Bredesen campaign responded to the attack by citing the former governors record on balancing the states budget without enacting an income tax or raising sales taxes.

"Governor Bredesen balanced eight budgets without imposing an income tax or increasing the sales tax on Tennessee families," Alyssa Hansen, press secretary for the Bredesen campaign, said. "He also worked diligently with the legislature to raise the tobacco tax to fund education and to close corporate tax loopholes that were siphoning resources away from public safety, health care, education, and other priorities," she added.

Bredsen's team also published a counter response on Wednesday through a digital ad title "The Attacks Have Started."

Democratic Missouri Sen. Claire McCaskill is also getting a taste of the Koch ad campaign. AFP is launching a $2.1 million ad, bashing her vote for President Barack Obama's Affordable Care Act and her husband's business dealings that led him to reportedly acquire $131 million.

"It's time to change our Senator," the McCaskill attack ad concludes.

The Baldwin and McCaskill races are marked as toss-ups by Larry Sabato's nonpartisan Crystal Ball.

The move by the Koch network to bash Democrats going into the final three months of the midterm elections comes after the network's leadership announced at their donor summit in Colorado Springs in July that they were open to supporting them.

"I know this is uncomfortable," Emily Seidel, the chief executive officer of Americans for Prosperity, told a group of donors at the time. "If you are a Democrat and stand up to [Sen.] Elizabeth Warren to corral enough votes for financial reform that breaks barriers for community banks and families, you're darn right we will work with you."

Charles Koch himself said he hopes to see people in power who will back policies that will "move toward a society, mutual benefit, equal rights, where everybody has the opportunity to realize their full potential." He added: "I don't care what initials are in front or after somebody's name."

Yet that acknowledgment by Koch set off a firestorm between his organization and the Trump White House.

After the summit, President Donald Trump responded on Twitter, calling the Koch network "a total joke," while Trump's former chief strategist Steve Bannon warned those candidates who accept Koch money will be punished.