The Koch brothers-backed conservative group Americans for Prosperity (AFP) is launching a major ad salvo against three Democratic senators — including a new member of its target list, Sen. Jeanne ShaheenCynthia (Jeanne) Jeanne ShaheenHomeland Security searching some social media doesn't violate privacy The feds shouldn't blackball Kaspersky without public evidence Week ahead: Crunch time for defense bill’s cyber reforms | Equifax under scrutiny MORE (D-N.H.).

The group is launching a seven-figure ad buy ripping Shaheen, as well as Sens. Kay HaganKay HaganLinking repatriation to job creation Former Sen. Kay Hagan in ICU after being rushed to hospital GOP senator floats retiring over gridlock MORE (D-N.C.) and Mary LandrieuMary LandrieuYou want to recall John McCain? Good luck, it will be impossible CNN producer on new O'Keefe video: Voters are 'stupid,' Trump is 'crazy' CNN's Van Jones: O'Keefe Russia 'nothingburger' video 'a hoax' MORE (D-La.), on ObamaCare. Americans for Prosperity has already been on the air against the other two, long viewed as top GOP targets in the 2014 elections.

The move against Shaheen shows the group believes she might be vulnerable in this year's election. Shaheen's poll numbers are solid, but not stellar, and former Sen. Scott Brown (R-Mass.) recently moved to New Hampshire and is seriously considering a run against her.

The ad against Landrieu shows clips of her and President Obama promising that everyone who has insurance can keep their plans, statements that have proven to be false. The ad against Hagan features a North Carolina woman saying she lost her insurance plan despite Hagan's promises and now faces major increases in her insurance rates.

"President Obama repeatedly promised Americans that they could keep their current health care plans and doctors if they chose, but millions have found out the hard way that this was the lie of the year," AFP President Tim Phillips says in a statement.

"We're putting pressure on senators who repeated that lie and doubled down on ObamaCare even as it became obvious that the law was hurting millions of Americans. The story of ObamaCare is one of less choice, rising premiums, and broken promises. AFP is committed to a long-term effort to stop this law.”

Americans for Prosperity has been the most active GOP-allied outside group since the last election concluded, and the newest salvo hints it is ready to spend much more than the $16 million already put into targeting Democrats on ObamaCare.