Joshua Roberts/Reuters
Donald Trump.
President Donald Trump threatened to campaign against a vulnerable Indiana Democrat, Sen. Joe Donnelly, if the senator votes against the GOP's tax reform plan, an outline of which the administration unveiled on Wednesday.
"If Sen. Donnelly doesn't approve it because you know, he is on the other side, we will come here. We will campaign against him like you wouldn't believe," Trump said at a rally at the Indiana State Fair Grounds, adding, "I think they're going to approve it. I think we'll have numerous Democrats come across."
Donnelly is widely viewed as one of the most vulnerable Democrats up for re-election in 2018, given Trump handily swept Indiana last November.
While the freshman senator has been an outspoken critic of international trade agreements that encourage outsourcing, including the North American Free Trade Agreement, the Associated Press revealed in July that, for at least a year, Donnelly's family business has used Mexican factories to produce dye for its ink pads.
Donnelly's brother owns the company, Stewart Superior Corp., and the senator served as a corporate officer and the company's general counsel prior to his election to Congress in 2006, and has reportedly invested up to $50,000 in the company.
Following the revelation, Donnelly, whom the GOP has dubbed "Mexico Joe," reportedly sold his stock in the business.
Republicans have jumped on the opportunity to attack Donnelly, who is widely seen as one of the most vulnerable Senate Democrats up for reelection in 2018 - due in part to Trump's 2016 victory in Indiana. He won the state by 19 points.
"Joe Donnelly can try to make Hoosiers forget about his family business's outsourcing controversy," an NRSC spokesman said in a press release, "but we'll make sure it's the first thing on voters' minds when they head to the polls in 2018."
Donnelly minimized his involvement in the company and called the accusation a distraction from his stance on outsourcing jobs.
"Some folks in Washington want to make the stock I've owned in my brother's company into a distraction from our work to end outsourcing," the senator said in a statement. "I won't let them distract us, so I'm selling the stock in my brother's company - a company I haven't had an active role in for 20 years."