A new poll from West Virginia shows that voter dissatisfaction with the current federal tax code could cost Joe Manchin his Senate seat.

A new poll commissioned by a group run by several former advisers to President Donald Trump shows that tax reform could be a pivotal issue in West Virginia’s 2018 Senate race. According to the poll from America First Policies, a majority of likely voters in West Virginia are dissatisfied with the current federal tax code, with more than a third saying they would be less likely to vote for Sen. Joe Manchin (D-W.V.) if he opposed congressional efforts to reform the tax code.

Independent voters who identify as conservative were the most likely to respond that they would be less likely to support Manchin, with 68 percent of them stating they would be less likely to vote for Manchin if he voted against tax reform legislation in the Senate that cut taxes for the middle class. Overall, 38 percent of those surveyed said they would be less likely to support Manchin if he voted against middle class tax cuts. Tax reform is also widely popular among likely voters with high levels of education, according to the poll. Sixty-seven percent of likely voters in the state with a college education or higher registered dissatisfaction with the current federal tax code.

Manchin, who was first elected to the Senate in 2010 after former Sen. Robert Byrd passed away, was elected to his first full term in 2012 and is believed to be one of the most vulnerable Senate incumbents in the 2018 election. A separate group, the Job Creators Network, which appears to be funded by a number of local industry trade groups and chambers of commerce, announced Monday that it planned to launch a multi-million-dollar ad campaign in West Virginia, North Dakota, and Montana on the topic of tax reform:

A conservative group is launching a six-figure television ad buy targeting Democratic senators in three states that President Donald Trump won, pressing them to embrace a Republican-led push for a tax overhaul. The ad buy from the Job Creators Network is the latest in what the group says will be a multi-million dollar campaign aimed at boosting GOP tax reform efforts. The 30-second spots will start airing Tuesday in West Virginia, Montana and North Dakota. They feature former President John F. Kennedy advocating for tax cuts as a means to boost the economy.

Tax reform proponents are increasing pressure on Sen. Heidi Heitkamp (D-N.D.) and Manchin, believing the two Democrat incumbents are the most likely to cross the aisle and vote for a Republican-authored tax bill in the Senate, where the measure’s fate is uncertain following Republican defections on major health-care reform legislation. Heitkamp recently took a high-profile ride with the president on Air Force One en route to a tax reform event in North Dakota. Heitkamp’s signature was also noticeably absent from a letter from Senate Democrats demanding that Trump agree to a number of restrictive conditions to win their support for any tax reform proposals. Both Manchin and Sen. Jon Tester (D-Mont.) declined to sign the letter as well.

The America First Policies poll, which was conducted by The Polling Company — previously owned by top Trump White House adviser Kellyanne Conway — and National Research, Inc., surveyed 400 likely voters in West Virginia from September 21 through September 24 and has a margin of error of +/- 4.9 percent. Half of the respondents were contacted via cell phone or the Internet.