Coburn, a doctor and former U.S. representative from Muskogee spent more than $1 million in the first two weeks of October, leaving him with only $60,828, according to his most recent campaign finance report. The Republican spent most of the money on radio and television advertising.
In that same two-week period, Representative Carson spent $839,000, leaving $624,537 in his account.
In addition to the spending spree by the candidates, independent groups have also poured money into advertising in the state.
Ads promoting Coburn have been funded by Americans United to Preserve Marriage, a group headed by former Republican presidential candidate Gary Bauer, and the Washington-based Club for Growth.net, which has spent about $500,000 in the Oklahoma race in the past few weeks.
Carson ads have been paid for by Citizens for a Strong Senate, a group funded by individuals in California, the Washington-based New Democratic Network and the national Democratic Party.
Meanwhile, Carson has picked up the endorsement of four of the largest American Indian tribes in Oklahoma, home to almost 250,000 American Indians or nearly 8 percent of the population. The tribal leaders praised Carson at an October rally, saying the representative brought home from Washington millions of dollars in rural roads and other infrastructure projects on tribal land.
Cherokee leader Chad Smith, a Republican, said he might have supported Coburn had he not heard a recording of comments Coburn made at a town hall meeting in Altus.
“Listen, I know the tribal issues; I was a congressman where most of the Indians are in this state,” Coburn said. “The problem is, most of them aren’t Indians. I mean this is a joke. It is one thing for us to keep our obligations to recognize Native Americans, but it’s a totally different thing for us to allow a primitive agreement with the Native Americans to undermine Oklahoma’s future and that’s what they’re talking about doing and it’s big money.”
Two tribal leaders gave their personal support to Coburn during a news conference that had been promoted as having nine tribal leaders endorsing the Republican.
During the conference Ken Chambers, chairman of the Seminole Nation, and Jeff Houser, chairman of the Fort Sill Apache Tribe, lent Coburn their support, but added they spoke only for themselves and not their tribes.
Houser said Coburn would help smaller tribes get land placed in trust so they could start enterprises to benefit tribal members.
Despite falling behind in funding, Coburn has maintained a slight lead in the latest polls. A week before Election Day, the Republican had a 3-point lead over the Democrat, according to a KWTV NEWS9 poll of about 500 registered Oklahoma voters who said they were likely to cast a ballot. The poll, which was conducted by Wilson Research Strategies, had a margin of error of 4.5 percentage points.
“[Coburn] does have a slim lead, but largely the debate is … going to have a lot to do with moving that 15 percent who are undecided right now,” said Bill Cullo of Wilson Research Strategies.