Coats, R-Indiana, said in an interview with ABC News that his opponent for the Senate seat, Democratic Rep. Brad Ellsworth, is the real insider in the race.
"Right now, he is," Coats said. "I'm a candidate running for office. Brad Ellsworth is an incumbent sitting in office. People are unhappy with what's happening in Washington under this administration. He was there; I wasn't."
Coats' attempt to return to Congress, after more than a decade out of office, marks something of a test case for how voters' anger is being directed this year.
Coats has the resume of the consummate insider Democrats contend that he still is. He served 20 years in the House and Senate and took an ambassador's post under President George W. Bush, before making millions as a Washington lobbyist.
The "insider" tag dogged him through the GOP primary. Coats last week prevailed over a tea party favorite, State Sen. Marlin Stutzman, and a former House member, John Hostettler, in a campaign in which his lobbying ties where a major issue.
Now, Indiana Republicans are rallying behind Coats in the hope that he can win the seat held by the retiring Democratic Sen. Evan Bayh.
Coats said he's stronger for the experience of having been through a primary -- and grateful that he's not seeking another Senate term from the perch of the U.S. Senate.
"Had I been an incumbent, I think it would have been a different -- probably a different story" in the primary, Coats said. "People were more willing to say, 'Well, he wasn't part of that.' I was able to share that I was just as disillusioned with some of the things as they were."
Democrats contend that Coats won't be able to shed the baggage he accumulated inside the Beltway.
"The only thing he's an outsider to in this race is Indiana, since he didn't even have a residence in Indiana until he decided he would run for the U.S. Senate," said Adam Elkington, a spokesman for the Indiana Democratic Party.
"Hoosiers have a clear choice in this race for Senate: a Washington, D.C., lobbyist who represents Wall Street banks, foreign nations and corporations that ship Hoosier jobs overseas, or a former sheriff from Evansville, Indiana, who will represent Hoosier families."
Democrats have hammered Coats over his lobbying for, among other clients, major Wall Street interests. His firm has done work for Merrill Lynch, Goldman Sachs, Bank of America, and the New York Stock Exchange.
Coats said Democrats are misconstruing his lobbying work. He promised to make public as many details as possible about his work -- "everything anybody wants to know" -- in the coming days, though he acknowledged some difficulties in disclosure owing to attorney-client privilege.
"I'm willing to sit down and explain it," Coats said. "The problem is attorney-client relationship. So it's a dilemma in the sense that you can't -- you're not in a position to disclose the positive in any kind of detail of what you did for them, but you're vulnerable to whatever the negative for whatever they say that it was."