Sen. Bob Corker, R-Tenn., declined to say who specifically gave him the information that Volkswagen would expand production at its Chattanooga, Tenn., facility even if the workers rejected an organizing bid by the United Auto Workers, but strongly hinted that his primary source was an outside consultant hired by VW.

"[After] five years of involvement with a company like this, from the very beginning to now, you end up developing relationships, not just with people all up and down the line that are inside the company, but also with those people who are doing the site selection process. The outside consultants. The people who are involved in crisis management for the company," Corker told the Washington Examiner.

Corker's claims that he had inside information about VW's plans have been a source of controversy since he first made them in a press release issued Feb. 12, midway through a three-day unionization vote at the Chattanooga plant. The UAW blamed its loss in part on Corker and filed a complaint on Feb. 21 with the National Labor Relations Board. The union says Corker's comments are sufficient reason to void their loss and hold a new vote.

The senator's comments ran contrary to prior indications from VW officials that it needed the Chattanooga plant to have a European-style "works council" in order to expand to include a new SUV line. Under U.S. labor law, a works council can only be allowed if the facility is also unionized.

In fact, VW had been cooperating with UAW during its bid unionize the workers. Based on that, many expected the union to win recognition.

After the first day of worker voting, Corker issued a press release that said: "I've had conversations today and based on those am assured that should the workers vote against the UAW, Volkswagen will announce in the coming weeks that it will manufacture its new mid-size SUV here in Chattanooga."

VW officials disputed Corker's claims, saying that there was "no connection" between expansion decision and the workers' vote.

Corker doubled down on his claim in a press release the following day: "After all these years and my involvement with Volkswagen, I would not have made the statement I made yesterday without being confident it was true and factual."

The comments incensed Big Labor officials, who saw it as a blatant attempt to influence the election by a senator long opposed to the UAW.

The senator downplayed the impact of the comments, pointing to reports that nearly two-thirds of the eligible voters had cast ballots by the time he made his comments. He said grassroots efforts to reach the VW workers had a bigger impact.

Corker, who was speaking at a breakfast hosted by the Christian Science Monitor, defended his opposition to unionization, saying UAW was making a bid at the plant only to get more dues money for itself.

He has warned that should the NLRB back UAW's complaint, that would muzzle lawmakers, preventing them from commenting on labor issues.

He said he did not expect to have to testify in any NRLB investigation: "I would doubt it since I am not a party to the case."