Multiple partisan groups are pouring millions of dollars into West Virginia in a bid to pressure conservative Democratic Sen. Joe Manchin over key pieces of his own party’s agenda.The TV ad blitz from both sides of the aisle launched as early as last month and has continued into June, according to data provided to CNBC by ad analytics company Medium Buying. Two of the groups are virtually unknown and have quietly been trying to make an impact in West Virginia in recent weeks.The ad war comes as the conservative Koch network pressures Manchin to oppose certain policies pushed by his fellow Democrats. It is also the latest illustration of the importance of Manchin’s vote. Democrats have a bare majority in the Senate, due to Vice President Kamala Harris’ tiebreaking vote, and Manchin is necessary for pretty much any legislation the party wants to pass.One group is End Citizens United/ Let America Vote, an organization dedicated to ending big money in politics and improving voters’ access to the ballot box. Its ad campaign urges support for the For the People Act, the Democratic-backed election bill that advocates say would curtail the influence of big money donors.The group started running digital ads in April and television spots in May in the Mountain State. The paid media side of the campaign is expected to cost $2.5 million, according to organizers.CNBC reviewed a copy of a new ad the group will run this weekend in West Virginia. Though it does not call out Manchin by name, it features Roger Champ, a veteran, who was presented the Purple Heart by the senator himself in 2017. “We need the For the People Act. It’s time for tough ethics rules,” Champ says in the ad.Manchin, in a recent op-ed, wrote that he opposed eliminating the filibuster and that he would not vote for the For the People Act, citing his desire for more bipartisanship. His words didn’t dissuade groups from trying to appeal to him, however.”We’ve been at it for months, and will continue to be there as long as Manchin continues to say inaction is not an option,” Adam Bozzi, vice president of communications for End Citizens United/Let America Vote, told CNBC in an email.Representatives for Manchin did not return requests for comment.A relatively new group, the West Virginia Freedom Alliance Action Fund, also wants Manchin to support the For the People Act. The group started running ads in West Virginia during late May.The organization has spent over $220,000 on both broadcast and cable TV ads since last month, according to Medium Buying. The most recent ad provided by Medium Buying to CNBC shows pictures of Manchin, while a voiceover says, “Only a great senator can break the gridlock in Washington, to lessen the power of big money, protect our right to vote and stop politicians drawing election maps that benefit one party and themselves.”That group is being represented by Blue West Media, a Colorado-based media agency. Bernie Sanders’ 2020 presidential campaign paid Blue West over $20 million for “media advertising,” according to FEC records. Blue West Media did not return a request for comment.Maintaining Mountain Values, another group that has eluded media scrutiny, is urging Manchin to oppose President Joe Biden’s $2 trillion infrastructure proposal. Since earlier this month, the organization has spent over $100,000 on broadcast and cable TV ads, according to Medium Buying.Medium Buying provided CNBC with a copy of Maintain Mountain Values’ most recent ad. “Their so-called infrastructure plan? It’s a geyser of waste, billions for green energy, electric vehicles and more government welfare,” a voiceover says during the ad. “Tell Joe Manchin to stop the radicals from pouring our tax dollars down the drain,” the voice says at the end of the ad.Federal Communications Commission documents show that Maintaining Mountain Values enlisted SRCP Media as its media consultant. That ad company lists the “Swift Boat Veterans For Truth” group, which targeted Democratic presidential nominee John Kerry in 2004, as one of their past clients. Other clients listed include former GOP presidential candidate Mitt Romney and the late Sen. John McCain’s presidential campaign in 2000.The treasurer on the FCC documents is Thomas Datwyler, who, according to his LinkedIn page, is a campaign finance compliance consultant.Data from the Center for Responsive Politics and Federal Election Commission records list Datwyler as a campaign treasurer for the failed congressional campaign of former Trump aide and federal prisoner George Papadopoulos, who was pardoned by former President Donald Trump; a super PAC that backed GOP Sen. Susan Collins of Maine; and other political organizations.SRCP and Datwyler did not return emailed requests for comment.