MILWAUKEE (AP) -- Ron Johnson spent millions to be the GOP's candidate to take on Wisconsin Sen. Russ Feingold.
Now the Republican businessman has to guard against the perception he's trying to buy the seat. He also has to contend with a far tougher opponent than the one he trounced in the primary.
Johnson has no political experience, but he had a convincing primary win Tuesday.
His rapid ascent reflects the personal wealth he poured into his Senate bid. Campaign finance reports show he invested $4.4 million.
Feingold has already begun attacking Johnson's credentials, accusing his rival last week of trying to buy the Senate seat.
Johnson has dismissed such talk. He says people are supporting him because they're tired of career politicians such as Feingold.