TD Ameritrade founder Joe Ricketts is the latest in a string of billionaires who have put their names and wallets on the line this election season.

The New York Times reported Thursday that Ricketts was considering spending $10 million on ads revisiting the controversy over President Obama's former pastor Jeremiah Wright.

By midday, Ricketts had backed away from that game plan, but earlier this week he paid for a big ad buy that helped propel a little-known Nebraska legislator to the Republican nomination for a U.S. Senate seat.

Ricketts has been a behind-the-scenes funder of conservative political causes for the past few years. He founded Taxpayers Against Earmarks, a group that railed against spending on pet projects by lawmakers in 2010.

In a Web video, he explained his political evolution: "I started my political life as a Kennedy Democrat, and Johnson pushed me out of the Democratic Party because he spent too much money. Reagan pulled me into the Republican Party, and Bush pushed me out because he spent too much money. So I am now a registered independent, and I probably will be that way for the rest of my life."

While the 70-year-old may be a registered independent, the vast majority of his political contributions have been to Republicans and against Democrats. He bankrolled an $862,000 campaign against Senate Majority Leader Harry Reid, a Nevada Democrat, two years ago. He contributed to nearly all of the Republicans running for president this year.

The Ending Spending Action Fund, the successor to the anti-earmark group, spent more than a quarter of a million dollars on ads in support of Deb Fischer, the state lawmaker who won a surprising victory in Tuesday's Republican U.S. Senate primary in Nebraska.

Ricketts has also contributed at least $100,000 to the Friends of Scott Walker, the campaign for the Republican governor of Wisconsin now engaged in a bitter recall election.

Ricketts has appeared on Forbes magazine's list of the 400 wealthiest Americans, and he's believed to have a net worth of $1 billion. He amassed his wealth as the founder of TD Ameritrade, the online stock trading firm he started in 1975 as First Omaha Securities.

The Nebraska native recalled his first job, as a third-grader, helping the janitor of a local courthouse. The job, he said, made his parents proud. "And I felt proud of myself, cleaning bathrooms, emptying wastebaskets and sweeping floors because I had a job where I got paid. So that has always been the main focus of my life and my energies — to make money. And it's a lot of fun to make money."

In 2008, Ricketts stepped down as Ameritrade's chairman. He still holds about 15 percent of the company's stock. Aside from conservative politics, he's involved in a number of eclectic ventures, including an education foundation, a bison ranch and a film production company.

Three years ago, a family trust purchased the Chicago Cubs.

"I can tell you my kids are dedicated with every ounce of energy that they have to win a World Series," he has said.

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