End Citizens United, a Democratic Party-friendly group focused on campaign finance reform, has begun airing two new ads charging Sen. Dean Heller with voting to please his political donors rather than his constituents.

One ad said that Heller has taken $220,000 from the pharmaceutical industry through the end of last month and cited his vote against legislation in 2007 that would have allowed the federal government to negotiate for lower prescription drug prices.

The other ad said Heller had taken $100,000 from “predatory lenders” and had “tried to shut down” the Consumer Financial Protection Bureau, which Heller, and most Republicans, argue needs to be restructured to make the agency more accountable to Congress.

“Senator Dean Heller is a top destination for corporate special interests and mega-donors looking to buy influence in the Senate,” ECU President Tiffany Muller said in a statement. “He’s taken money from big money special interests like the pharmaceutical and payday loan industries, and worked for them in the Senate. He has voted for legislation that protects his donors’ interests, and Nevadans are paying the price.”

The group, which supports Heller’s Democratic opponent, Rep. Jacky Rosen, spent $2 million in total, with $1.7 million going toward the ads, which will air on broadcast and cable television between Aug. 1 and Aug. 17. ECU will also run about $350,000 of digital ads through August aimed at statewide millennial voters deemed persuadable.

Michael McAdams, a spokesman for the National Republican Senatorial Campaign Committee, suggested that ECU was hypocritical, citing instances where Rosen has benefited from current campaign finance laws, including when Tom Steyer, a billionaire environmentalist, announced in March that he would pledge to spend $2 million to help elect Rosen.

"Jacky Rosen has stayed silent while California billionaires and dark money groups have spent millions of dollars boosting her failing campaign," McAdams said. "It's clear Rosen and End Citizens United are only against dark money when they're not the ones benefiting from it."

Running in one of the most watched Senate races in the country, Heller is the only Republican seeking re-election in a state Hillary Clinton won. The race, which could also determine control of the Senate, has been increasing in intensity with both sides looking for any edge.

In a poll commissioned by the Reno Gazette Journal released Tuesday, Heller leads Rosen by one point.

This isn’t the first time ECU has dipped into Nevada political races. In 2016, the group spent $2 million for Sen. Catherine Cortez Masto and $150,000 for Rosen during her congressional campaign.

The group did some polling in connection with Cortez Masto’s race that showed that their message of campaign finance reform worked in Nevada. The poll showed that Latinos and independents were two of the groups for which the money-in-politics message most resonated.

Earlier this year, ECU also ran $300,000 in digital ads focused on Heller’s vacillating on his support for the Affordable Care Act, which is popular in the state.

Named for the landmark 2010 Supreme Court case, Citizens United v FEC, that overturned limits on corporate and union donations to political campaigns, the group said that outside political spending in Nevada has increased over roughly the last decade.

In 2006, $277,000 in outside spending was devoted to the Senate race. By 2016, after Citizens United, outside spending had ballooned to $97 million.