By Justin Sink
Rehberg, meanwhile has been hammering Tester as an ally of President Barack Obama, who remains unpopular in the state, especially on the issue of healthcare reform.
But Rehberg has also had to grapple with reports that he received tens of thousands of dollars last year from lobbyists who did not properly disclose their place of employment. Rehberg has hammered Tester as a top recipient of lobbyist campaign funding.
"We not only comply with the law, we make every effort to go above and beyond it," said Chris Bond, a spokesman for Rep. Rehberg, in a statement to The Hill.
"This is all done in the light of day in publicly available documents and we believe that transparency is a good thing, because it allows folks in Montana to know that contrary to his rhetoric, Jon Tester is the number one recipient of lobbyist campaign cash in the country."
Julian Pecquet contributed to the reporting of this article.