The latest public opinion poll in Colorado indicates that Republican Senate challenger Joe O’Dea trails Democratic Sen. Michael Bennet by just six points among those who say they’ll definitely vote in November’s midterm elections.

According to a Marist College Poll conducted Oct. 3-6 and released on Tuesday, Bennet tops O’Dea 49%-43%. And among independent voters, the incumbent Democrat holds a narrow 43%-40% edge over the GOP nominee, with 13% undecided.

O’Dea, a Denver area construction company owner and first-time candidate, is challenging Bennet, a former superintendent of the Denver Public Schools who’s held the Senate seat in Colorado since 2009, in a race that became increasingly competitive over the summer and could become one of a handful that determines if Republicans win back the chamber's majority in next month’s elections.

An average of all the latest public opinion surveys in the race compiled by Real Clear Politics puts Bennet up 7.7 points over O’Dea.

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Joe O'Dea

Joe O'Dea, Republican nominee for the U.S. Senate seat held by Democrat Michael Bennet, speaks during a primary election night watch party, late June 28, 2022, in Denver. (AP Photo/David Zalubowski)

"Nearly four in ten Colorado adults (39%) have a favorable opinion of Bennet. 31% have an unfavorable view of him, and 30% have either never heard of Bennet or are unsure how to rate him. O’Dea’s favorable score is upside down (27% favorable to 34% unfavorable). Nearly four in ten (38%) have either never heard of O’Dea or are unsure how to rate him," the release from Marist notes.

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Once a battleground state, Colorado has leaned blue for nearly two decades and President Biden captured the state by 13 points in the 2020 presidential election. But following O'Dea's victory in the late June GOP primary, Republicans have become increasingly optimistic that they can flip Bennet's seat from blue to red. 

And in recent weeks he’s been supported by some high-profile GOP surrogates on the Colorado campaign trail — from Sen. Tom Cotton of Arkansas two weeks ago to Sen. Tim Scott of South Carolina last week. And former President George W. Bush is headed to Colorado in the coming days to headline a fundraiser for O’Dea.

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Meanwhile, the Senate Leadership Fund, the top outside group backing Senate GOP incumbents and candidates and aligned with longtime Republican Leader Mitch McConnell, is making its first expenditures in Colorado, Fox News has confirmed.

Fox News power rankings

Fox News Power Rankings indicating the political leanings of the states for the Senate. Democrats lean 2, 1 likely, and 8 solid. GOP lean 4, 2 likely, and 14 solid. Toss up at 4. (Fox News)

The Senate Leadership Fund on Friday made a $1.25 million contribution to the pro-O’Dea super PAC American Policy Fund. While that’s not a particularly large spend by SLF standards, the group’s spokesperson Jack Pandol told Fox News they "aren’t closing the door on further investment" in Colorado, and are "keeping an eye on" the race with four weeks to go until Election Day.

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During Colorado’s GOP Senate primary, pro-Democratic groups meddling in the Republican contest spent big bucks to beef up the conservative credentials of Republican rival Ron Hanks and framed O'Dea as a moderate. Democrats viewed Hanks — who attended then-President Donald Trump's Jan. 6, 2021, in the nation’s capital ahead of the storming of the U.S. Capitol, and who took a hardline against legalized abortion — as the weaker general election candidate.

But O'Dea won the primary, and now Democrats are trying to portray him as a far-right conservative.