Republicans are accusing Rep. Bruce Braley (D., Iowa) of supporting environmentalist causes at the expense of Iowa farmers and residents to appease one of the largest funders of his Senate campaign.

The Iowa Democrat received a boost recently when NextGen Climate Action Committee, the Super PAC funded by billionaire environmentalist Tom Steyer, announced a $2.6 million ad buy in the state targeting Republican candidate Joni Ernst.

Steyer also donated $5 million of his personal money in April to NextGen Climate and earmarked it for the Senate Majority PAC. The PAC, run by former staffers for Senate Majority Leader Harry Reid (D., Nev.), has purchased almost $2 million worth of ad buys this year either in support of Braley or opposing Ernst, according to Federal Election Commission (FEC) records.

The GOP says Braley’s votes in Congress align with the environmental activism of Steyer.

Braley voted against a successful amendment to the House farm bill twice last month. The measure eliminated a requirement that farmers obtain an extra permit to use pesticides already approved under federal law, or face what opponents described as a costly fine.

Sen. Chuck Grassley (R., Iowa) in May called the pesticide requirement one of the Environmental Protection Agency’s (EPA) "heavy-handed" regulations that "threaten the very livelihood of farmers and rural communities." Braley was the only member of the Iowa House delegation to oppose the amendment to the EPA regulation.

"With millions of campaign dollars at stake, Bruce Braley put extreme environmentalist Tom Steyer’s agenda before the interests of farmers in the Hawkeye State," said Republican Party of Iowa spokesman Jahan Wilcox in a recent statement. "It’s just the latest example of Braley pledging his allegiance to Steyer, so he can spend six more years in Washington."

Braley’s campaign did not respond to a request for comment.

The four-term congressman has also switched his position on the Keystone XL pipeline.

Braley initially praised the pipeline project in 2012 as an "opportunity to create thousands of jobs in Iowa and the Midwest and reduce our dependence on Middle Eastern oil." However, he voted against a House bill in May 2013 that called for construction of the pipeline.

The Obama administration has indefinitely delayed approval of the project despite its potential to create jobs and minimal environmental impact, according to findings by the State Department earlier this year. Steyer has pledged to back anti-Keystone lawmakers as part of his plans to spend at least $100 million in this fall’s midterm elections.

It remains unclear whether Braley and Steyer’s environmental advocacy will resonated with Iowans. Just 2 percent of registered voters in the state say the environment should be a top priority for political leaders, according to surveys in March and June. More than 20 percent of voters in both polls said the economy and jobs should be the most important issue.

The first ad by Steyer’s NextGen Climate in Iowa, which accused Ernst of protecting tax breaks for companies that outsource jobs overseas, was rated "False" by PolitiFact. Similar ads were debunked as false by multiple fact-checking groups during the 2010 election cycle.

Ernst campaign spokeswoman Gretchen Hamel said on Wednesday that a second NextGen Climate ad should be taken down. That ad claims Ernst is against renewable fuels in Iowa and again criticizes her for supporting tax breaks that would purportedly hurt Iowa jobs.

"This is a blatantly false ad that should be taken off the airwaves immediately," Hamel said in an emailed statement. "The ad has already been fact checked as false and the very column they cite also states, ‘Joni will passionately stand in defense of [the Renewable Fuel Standard].’ Bruce Braley and his environmentalist billionaire friends are trying to fool Iowans and it’s unacceptable."

Additionally, Braley continues to be plagued by accusations that he is out of touch with Iowa voters. The former trial lawyer called Sen. Grassley a "farmer from Iowa who never went to law school" at a January fundraiser attended by other lawyers, comments that many viewed as elitist in the farmer-heavy state. Braley’s poll numbers dropped after a video of his remarks surfaced earlier this year.

Braley and Ernst are currently in a dead heat in the Iowa Senate race, according to the Real Clear Politics poll average. The state could be crucial to Republicans’ efforts to retake the Senate majority this fall.