Sen. Bernie Sanders (I-Vt.) received a nod Wednesday from an unlikely source: Freedom Partners, a political nonprofit with close ties to billionaire conservatives Charles and David Koch.

Freedom Partners released an ad Wednesday that it says is meant to encourage moderators of the upcoming Democratic debate to raise the issue of the Export-Import Bank, a federal agency that free-market groups like Freedom Partners have characterized as "corporate welfare."

The Ex-Im Bank, as it's known, helps to finance foreign purchases of U.S.-made goods for large-scale buyers that need to borrow money to make the purchase. Critics of the bank have said that it disproportionately helps major corporations and that it could do more to assist small businesses.

“Seventy-five percent of the funds going from the federal government to the Export-Import Bank goes to large, profitable corporations," Sanders says in the Freedom Partners ad, in a clip from the Democratic debate in Flint, Michigan, this past Sunday. "I don’t think it’s a great idea for the American taxpayer to have to subsidize, through corporate welfare, profitable corporations."

“I don’t want to break the bad news -- Democrats are not always right," Sanders said during that debate. "Democrats have often supported corporate welfare.”

"Tonight, we’d like to see moderators push both candidates to explain why middle class Americans should be lining the pockets of major corporations and their campaign donors," Andy Koenig, a senior policy adviser at Freedom Partners, said in a statement Wednesday.

The group also hopes to raise the visibility of other kinds of government breaks for corporations, including wind and solar tax credits and sugar subsidies.

Earlier this week, the National Rifle Association, another group reviled by progressives and many Democrats, expressed its support for Sanders via Twitter.

The NRA and the Sanders campaign did not immediately respond to requests for comment.