An anti-Franken television ad emerges

The fight to unseat Democratic U.S. Sen. Al Franken has entered the airwaves.

American Encore, a conservative group that appears to be associated with the better known Americans for Job Security, has posted an ad online and is launching a television campaign to air claims that Franken has attacked "free speech."

The founder of the group, which is closely aligned with big Republican funders Charles and David Koch, said it will spend a quarter of a million dollars to air the ad.

Founder Sean Noble told the Wall Street Journal that it "plan spend about $10 million influencing congressional races this year."

While most political handicappers believe that Republicans will have a tough time ousting Franken his this, his whisper thin victory in his first election and his high profile status makes him a ripe target.

The spending follows long warnings from the Franken campaign that the Kochs would come after him. More than a dozen times this year, his campaign has used fear of Kochs attacks to solicit donations.On Wednesday morning, Democratic operative Paul Begala told supporters about a new anti-Franken Super PAC, adding "this is a whole different challenge than any of the Super PACs you already know about -- the Koch brothers, Karl Rove, etc."

Alexandra Fetissoff, Franken campaign spokeswoman, said the ad was "ridiculous."

At issue: regulations on what political non-profits need to disclose about their spending. These regulations currently require less disclosure from groups like American Encore, Americans for Job Security as well as nonprofits from the left than they do other big spenders.

In 2012, well before the Internal Revenue Service was under attack for targeting nonprofits from the right, Franken asked federal officials to make sure that nonprofits were not using their status to evade campaign finance disclosure. His request was neutral about the political viewpoints of the groups doing the politicking.

In 2013, once the IRS scandal broke, Franken joined the chorus of voices to say that the tax agency's work should be "done in a completely nonpartisan way."

Here's the ad at issue: