ND-Sen: Conservative group surprisingly thanks Dem with ad buy in very tight race. Here's why.

Sen. Heidi Heitkamp (D-N.D.) stands to lose her Senate seat this November to Rep. Kevin Cramer (R-N.D.), but the moderate Democrat just received a boost from an unlikely ally: Americans for Prosperity, a conservative nonprofit political advocacy group owned by the Koch brothers.

What are the details?

Last week, AFP made a digital ad buy thanking Heitkamp for supporting legislation that recently rolled back many of the Obama-era Dodd-Frank financial regulations.

"Thank you, Sen. Heitkamp for giving Main Street relief," the ad said.

The legislation's success was considered a victory for Republicans. Democrats opposed the legislation because they believe it will allow major banks to commit similar mistakes to the ones that led to the 2008 economic downturn. However, the bill only rolled back regulations on small and midsize banks, not major banks like Wells Fargo, Citi, Chase, Bank of America and others.

"This was a bipartisan effort made possible by lawmakers like Heidi Heitkamp who put politics aside to work together," AFP president Tim Phillips told Politico. "While we don't agree with Sen. Heitkamp on everything, particularly her vote against tax relief, we commend her for taking a stand against the leaders of her party to do the right thing."

As Politico noted, AFP's ad buy came just a week after President Donald Trump thanked Heitkamp at the White House for her work in passing the bill.

Is Heitkamp posturing?

While the junior North Dakota senator is considered a moderate Democrat, she has recently moved closer to the center in preparation for the race with Cramer, even disavowing Hillary Clinton after supporting her during the 2016 presidential election.

In a new television ad released last month, Heitkamp boasted of her conservative accolades.

"She led the fight to open up markets for North Dakota oil. Republicans say she’s ‘stronger than battery acid’ and ‘interested in getting things done.’ And newspapers [call her] a ‘rare senator’ who ‘often votes against party.' The most conservative Democrat in Washington," the ad declared.

Heitkamp is running unopposed in the Democratic primary election on June 12.